213 files changed, 33373 insertions, 0 deletions

diff --git a/bin/.gitignore b/bin/.gitignore
new file mode 100644
index 00000000..df322fd4
--- /dev/null
+++ b/bin/.gitignore
@@ -0,0 +1,36 @@
+*.html
+*.o
+beef
+bibsort
+bit
+bri
+c
+config.mk
+dtch
+ever
+fbatt
+fbclock
+glitch
+hi
+hnel
+modem
+nudge
+open
+order
+pbcopy
+pbd
+pbpaste
+pngo
+psf2png
+psfed
+ptee
+relay
+scheme
+scheme.h
+shotty
+tags
+title
+ttpre
+up
+when
+xx
diff --git a/bin/1sh/.gitignore b/bin/1sh/.gitignore
new file mode 100644
index 00000000..54db1cf1
--- /dev/null
+++ b/bin/1sh/.gitignore
@@ -0,0 +1,13 @@
+*.o
+.depend
+1sh
+builtins.c
+builtins.h
+config.mk
+mknodes
+mksyntax
+nodes.c
+nodes.h
+syntax.c
+syntax.h
+token.h
diff --git a/bin/1sh/1sh-kill.1 b/bin/1sh/1sh-kill.1
new file mode 100644
index 00000000..110fab7d
--- /dev/null
+++ b/bin/1sh/1sh-kill.1
@@ -0,0 +1,157 @@
+.\"-
+.\" Copyright (c) 1980, 1990, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the Institute of Electrical and Electronics Engineers, Inc.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"	@(#)kill.1	8.2 (Berkeley) 4/28/95
+.\" $FreeBSD: releng/12.1/bin/kill/kill.1 314436 2017-02-28 23:42:47Z imp $
+.\"
+.Dd October 3, 2016
+.Dt 1SH-KILL 1
+.Os
+.Sh NAME
+.Nm kill
+.Nd terminate or signal a process
+.Sh SYNOPSIS
+.Nm
+.Op Fl s Ar signal_name
+.Ar pid ...
+.Nm
+.Fl l
+.Op Ar exit_status
+.Nm
+.Fl Ar signal_name
+.Ar pid ...
+.Nm
+.Fl Ar signal_number
+.Ar pid ...
+.Sh DESCRIPTION
+The
+.Nm
+utility sends a signal to the processes specified by the
+.Ar pid
+operands.
+.Pp
+Only the super-user may send signals to other users' processes.
+.Pp
+The options are as follows:
+.Bl -tag -width indent
+.It Fl s Ar signal_name
+A symbolic signal name specifying the signal to be sent instead of the
+default
+.Dv TERM .
+.It Fl l Op Ar exit_status
+If no operand is given, list the signal names; otherwise, write
+the signal name corresponding to
+.Ar exit_status .
+.It Fl Ar signal_name
+A symbolic signal name specifying the signal to be sent instead of the
+default
+.Dv TERM .
+.It Fl Ar signal_number
+A non-negative decimal integer, specifying the signal to be sent instead
+of the default
+.Dv TERM .
+.El
+.Pp
+The following PIDs have special meanings:
+.Bl -tag -width indent
+.It -1
+If superuser, broadcast the signal to all processes; otherwise broadcast
+to all processes belonging to the user.
+.El
+.Pp
+Some of the more commonly used signals:
+.Pp
+.Bl -tag -width indent -compact
+.It 1
+HUP (hang up)
+.It 2
+INT (interrupt)
+.It 3
+QUIT (quit)
+.It 6
+ABRT (abort)
+.It 9
+KILL (non-catchable, non-ignorable kill)
+.It 14
+ALRM (alarm clock)
+.It 15
+TERM (software termination signal)
+.El
+.Pp
+Some shells may provide a builtin
+.Nm
+command which is similar or identical to this utility.
+Consult the
+.Xr builtin 1
+manual page.
+.Sh EXIT STATUS
+.Ex -std
+.Sh EXAMPLES
+Terminate
+the processes with PIDs 142 and 157:
+.Pp
+.Dl "kill 142 157"
+.Pp
+Send the hangup signal
+.Pq Dv SIGHUP
+to the process with PID 507:
+.Pp
+.Dl "kill -s HUP 507"
+.Pp
+Terminate the process group with PGID 117:
+.Pp
+.Dl "kill -- -117"
+.Sh SEE ALSO
+.Xr builtin 1 ,
+.Xr csh 1 ,
+.Xr killall 1 ,
+.Xr ps 1 ,
+.Xr sh 1 ,
+.Xr kill 2 ,
+.Xr sigaction 2
+.Sh STANDARDS
+The
+.Nm
+utility is expected to be
+.St -p1003.2
+compatible.
+.Sh HISTORY
+A
+.Nm
+command appeared in
+.At v3
+in section 8 of the manual.
+.Sh BUGS
+A replacement for the command
+.Dq Li kill 0
+for
+.Xr csh 1
+users should be provided.
diff --git a/bin/1sh/1sh-printf.1 b/bin/1sh/1sh-printf.1
new file mode 100644
index 00000000..33c4b9f5
--- /dev/null
+++ b/bin/1sh/1sh-printf.1
@@ -0,0 +1,385 @@
+.\" Copyright (c) 1989, 1990, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the Institute of Electrical and Electronics Engineers, Inc.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"	@(#)printf.1	8.1 (Berkeley) 6/6/93
+.\" $FreeBSD: releng/12.1/usr.bin/printf/printf.1 350613 2019-08-05 20:19:38Z jilles $
+.\"
+.Dd July 29, 2019
+.Dt 1SH-PRINTF 1
+.Os
+.Sh NAME
+.Nm printf
+.Nd formatted output
+.Sh SYNOPSIS
+.Nm
+.Ar format Op Ar arguments ...
+.Sh DESCRIPTION
+The
+.Nm
+utility formats and prints its arguments, after the first, under control
+of the
+.Ar format .
+The
+.Ar format
+is a character string which contains three types of objects: plain characters,
+which are simply copied to standard output, character escape sequences which
+are converted and copied to the standard output, and format specifications,
+each of which causes printing of the next successive
+.Ar argument .
+.Pp
+The
+.Ar arguments
+after the first are treated as strings if the corresponding format is
+either
+.Cm c , b
+or
+.Cm s ;
+otherwise it is evaluated as a C constant, with the following extensions:
+.Pp
+.Bl -bullet -offset indent -compact
+.It
+A leading plus or minus sign is allowed.
+.It
+If the leading character is a single or double quote, the value is the
+character code of the next character.
+.El
+.Pp
+The format string is reused as often as necessary to satisfy the
+.Ar arguments .
+Any extra format specifications are evaluated with zero or the null
+string.
+.Pp
+Character escape sequences are in backslash notation as defined in the
+.St -ansiC ,
+with extensions.
+The characters and their meanings
+are as follows:
+.Pp
+.Bl -tag -width Ds -offset indent -compact
+.It Cm \ea
+Write a <bell> character.
+.It Cm \eb
+Write a <backspace> character.
+.It Cm \ef
+Write a <form-feed> character.
+.It Cm \en
+Write a <new-line> character.
+.It Cm \er
+Write a <carriage return> character.
+.It Cm \et
+Write a <tab> character.
+.It Cm \ev
+Write a <vertical tab> character.
+.It Cm \e\'
+Write a <single quote> character.
+.It Cm \e\e
+Write a backslash character.
+.It Cm \e Ns Ar num
+Write a byte whose
+value is the 1-, 2-, or 3-digit
+octal number
+.Ar num .
+Multibyte characters can be constructed using multiple
+.Cm \e Ns Ar num
+sequences.
+.El
+.Pp
+Each format specification is introduced by the percent character
+(``%'').
+The remainder of the format specification includes,
+in the following order:
+.Bl -tag -width Ds
+.It "Zero or more of the following flags:"
+.Bl -tag -width Ds
+.It Cm #
+A `#' character
+specifying that the value should be printed in an ``alternate form''.
+For
+.Cm b , c , d , s
+and
+.Cm u
+formats, this option has no effect.
+For the
+.Cm o
+formats the precision of the number is increased to force the first
+character of the output string to a zero.
+For the
+.Cm x
+.Pq Cm X
+format, a non-zero result has the string
+.Li 0x
+.Pq Li 0X
+prepended to it.
+For
+.Cm a , A , e , E , f , F , g
+and
+.Cm G
+formats, the result will always contain a decimal point, even if no
+digits follow the point (normally, a decimal point only appears in the
+results of those formats if a digit follows the decimal point).
+For
+.Cm g
+and
+.Cm G
+formats, trailing zeros are not removed from the result as they
+would otherwise be;
+.It Cm \&\-
+A minus sign `\-' which specifies
+.Em left adjustment
+of the output in the indicated field;
+.It Cm \&+
+A `+' character specifying that there should always be
+a sign placed before the number when using signed formats.
+.It Sq \&\ \&
+A space specifying that a blank should be left before a positive number
+for a signed format.
+A `+' overrides a space if both are used;
+.It Cm \&0
+A zero `0' character indicating that zero-padding should be used
+rather than blank-padding.
+A `\-' overrides a `0' if both are used;
+.El
+.It "Field Width:"
+An optional digit string specifying a
+.Em field width ;
+if the output string has fewer bytes than the field width it will
+be blank-padded on the left (or right, if the left-adjustment indicator
+has been given) to make up the field width (note that a leading zero
+is a flag, but an embedded zero is part of a field width);
+.It Precision:
+An optional period,
+.Sq Cm \&.\& ,
+followed by an optional digit string giving a
+.Em precision
+which specifies the number of digits to appear after the decimal point,
+for
+.Cm e
+and
+.Cm f
+formats, or the maximum number of bytes to be printed
+from a string; if the digit string is missing, the precision is treated
+as zero;
+.It Format:
+A character which indicates the type of format to use (one of
+.Cm diouxXfFeEgGaAcsb ) .
+The uppercase formats differ from their lowercase counterparts only in
+that the output of the former is entirely in uppercase.
+The floating-point format specifiers
+.Pq Cm fFeEgGaA
+may be prefixed by an
+.Cm L
+to request that additional precision be used, if available.
+.El
+.Pp
+A field width or precision may be
+.Sq Cm \&*
+instead of a digit string.
+In this case an
+.Ar argument
+supplies the field width or precision.
+.Pp
+The format characters and their meanings are:
+.Bl -tag -width Fl
+.It Cm diouXx
+The
+.Ar argument
+is printed as a signed decimal (d or i), unsigned octal, unsigned decimal,
+or unsigned hexadecimal (X or x), respectively.
+.It Cm fF
+The
+.Ar argument
+is printed in the style `[\-]ddd.ddd' where the number of d's
+after the decimal point is equal to the precision specification for
+the argument.
+If the precision is missing, 6 digits are given; if the precision
+is explicitly 0, no digits and no decimal point are printed.
+The values \*[If] and \*[Na] are printed as
+.Ql inf
+and
+.Ql nan ,
+respectively.
+.It Cm eE
+The
+.Ar argument
+is printed in the style
+.Cm e
+.Sm off
+.Sq Op - Ar d.ddd No \(+- Ar dd
+.Sm on
+where there
+is one digit before the decimal point and the number after is equal to
+the precision specification for the argument; when the precision is
+missing, 6 digits are produced.
+The values \*[If] and \*[Na] are printed as
+.Ql inf
+and
+.Ql nan ,
+respectively.
+.It Cm gG
+The
+.Ar argument
+is printed in style
+.Cm f
+.Pq Cm F
+or in style
+.Cm e
+.Pq Cm E
+whichever gives full precision in minimum space.
+.It Cm aA
+The
+.Ar argument
+is printed in style
+.Sm off
+.Sq Op - Ar h.hhh No \(+- Li p Ar d
+.Sm on
+where there is one digit before the hexadecimal point and the number
+after is equal to the precision specification for the argument;
+when the precision is missing, enough digits are produced to convey
+the argument's exact double-precision floating-point representation.
+The values \*[If] and \*[Na] are printed as
+.Ql inf
+and
+.Ql nan ,
+respectively.
+.It Cm c
+The first byte of
+.Ar argument
+is printed.
+.It Cm s
+Bytes from the string
+.Ar argument
+are printed until the end is reached or until the number of bytes
+indicated by the precision specification is reached; however if the
+precision is 0 or missing, the string is printed entirely.
+.It Cm b
+As for
+.Cm s ,
+but interpret character escapes in backslash notation in the string
+.Ar argument .
+The permitted escape sequences are slightly different in that
+octal escapes are
+.Cm \e0 Ns Ar num
+instead of
+.Cm \e Ns Ar num
+and that an additional escape sequence
+.Cm \ec
+stops further output from this
+.Nm
+invocation.
+.It Cm n$
+Allows reordering of the output according to
+.Ar argument .
+.It Cm \&%
+Print a `%'; no argument is used.
+.El
+.Pp
+The decimal point
+character is defined in the program's locale (category
+.Dv LC_NUMERIC ) .
+.Pp
+In no case does a non-existent or small field width cause truncation of
+a field; padding takes place only if the specified field width exceeds
+the actual width.
+.Pp
+Some shells may provide a builtin
+.Nm
+command which is similar or identical to this utility.
+Consult the
+.Xr builtin 1
+manual page.
+.Sh EXIT STATUS
+.Ex -std
+.Sh COMPATIBILITY
+The traditional
+.Bx
+behavior of converting arguments of numeric formats not beginning
+with a digit to the
+.Tn ASCII
+code of the first character is not supported.
+.Sh SEE ALSO
+.Xr builtin 1 ,
+.Xr echo 1 ,
+.Xr sh 1 ,
+.Xr printf 3
+.Sh STANDARDS
+The
+.Nm
+command is expected to be compatible with the
+.St -p1003.2
+specification.
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.Bx 4.3 Reno .
+It is modeled
+after the standard library function,
+.Xr printf 3 .
+.Sh CAVEATS
+.Tn ANSI
+hexadecimal character constants were deliberately not provided.
+.Pp
+Trying to print a dash ("-") as the first character causes
+.Nm
+to interpret the dash as a program argument.
+.Nm --
+must be used before
+.Ar format .
+.Pp
+If the locale contains multibyte characters
+(such as UTF-8),
+the
+.Cm c
+format and
+.Cm b
+and
+.Cm s
+formats with a precision
+may not operate as expected.
+.Sh BUGS
+Since the floating point numbers are translated from
+.Tn ASCII
+to floating-point and
+then back again, floating-point precision may be lost.
+(By default, the number is translated to an IEEE-754 double-precision
+value before being printed.
+The
+.Cm L
+modifier may produce additional precision, depending on the hardware platform.)
+.Pp
+The escape sequence \e000 is the string terminator.
+When present in the argument for the
+.Cm b
+format, the argument will be truncated at the \e000 character.
+.Pp
+Multibyte characters are not recognized in format strings (this is only
+a problem if
+.Ql %
+can appear inside a multibyte character).
diff --git a/bin/1sh/1sh-test.1 b/bin/1sh/1sh-test.1
new file mode 100644
index 00000000..8ad8d0f4
--- /dev/null
+++ b/bin/1sh/1sh-test.1
@@ -0,0 +1,395 @@
+.\"-
+.\" Copyright (c) 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the Institute of Electrical and Electronics Engineers, Inc.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)test.1	8.1 (Berkeley) 5/31/93
+.\" $FreeBSD: releng/12.1/bin/test/test.1 314436 2017-02-28 23:42:47Z imp $
+.\"
+.Dd October 5, 2016
+.Dt 1SH-TEST 1
+.Os
+.Sh NAME
+.Nm test ,
+.Nm \&[
+.Nd condition evaluation utility
+.Sh SYNOPSIS
+.Nm
+.Ar expression
+.Nm \&[
+.Ar expression Cm \&]
+.Sh DESCRIPTION
+The
+.Nm
+utility evaluates the expression and, if it evaluates
+to true, returns a zero (true) exit status; otherwise
+it returns 1 (false).
+If there is no expression,
+.Nm
+also
+returns 1 (false).
+.Pp
+All operators and flags are separate arguments to the
+.Nm
+utility.
+.Pp
+The following primaries are used to construct expression:
+.Bl -tag -width Ar
+.It Fl b Ar file
+True if
+.Ar file
+exists and is a block special
+file.
+.It Fl c Ar file
+True if
+.Ar file
+exists and is a character
+special file.
+.It Fl d Ar file
+True if
+.Ar file
+exists and is a directory.
+.It Fl e Ar file
+True if
+.Ar file
+exists (regardless of type).
+.It Fl f Ar file
+True if
+.Ar file
+exists and is a regular file.
+.It Fl g Ar file
+True if
+.Ar file
+exists and its set group ID flag
+is set.
+.It Fl h Ar file
+True if
+.Ar file
+exists and is a symbolic link.
+This operator is retained for compatibility with previous versions of
+this program.
+Do not rely on its existence; use
+.Fl L
+instead.
+.It Fl k Ar file
+True if
+.Ar file
+exists and its sticky bit is set.
+.It Fl n Ar string
+True if the length of
+.Ar string
+is nonzero.
+.It Fl p Ar file
+True if
+.Ar file
+is a named pipe
+.Pq Tn FIFO .
+.It Fl r Ar file
+True if
+.Ar file
+exists and is readable.
+.It Fl s Ar file
+True if
+.Ar file
+exists and has a size greater
+than zero.
+.It Fl t Ar file_descriptor
+True if the file whose file descriptor number
+is
+.Ar file_descriptor
+is open and is associated with a terminal.
+.It Fl u Ar file
+True if
+.Ar file
+exists and its set user ID flag
+is set.
+.It Fl w Ar file
+True if
+.Ar file
+exists and is writable.
+True
+indicates only that the write flag is on.
+The file is not writable on a read-only file
+system even if this test indicates true.
+.It Fl x Ar file
+True if
+.Ar file
+exists and is executable.
+True
+indicates only that the execute flag is on.
+If
+.Ar file
+is a directory, true indicates that
+.Ar file
+can be searched.
+.It Fl z Ar string
+True if the length of
+.Ar string
+is zero.
+.It Fl L Ar file
+True if
+.Ar file
+exists and is a symbolic link.
+.It Fl O Ar file
+True if
+.Ar file
+exists and its owner matches the effective user id of this process.
+.It Fl G Ar file
+True if
+.Ar file
+exists and its group matches the effective group id of this process.
+.It Fl S Ar file
+True if
+.Ar file
+exists and is a socket.
+.It Ar file1 Fl nt Ar file2
+True if
+.Ar file1
+exists and is newer than
+.Ar file2 .
+.It Ar file1 Fl ot Ar file2
+True if
+.Ar file1
+exists and is older than
+.Ar file2 .
+.It Ar file1 Fl ef Ar file2
+True if
+.Ar file1
+and
+.Ar file2
+exist and refer to the same file.
+.It Ar string
+True if
+.Ar string
+is not the null
+string.
+.It Ar s1 Cm = Ar s2
+True if the strings
+.Ar s1
+and
+.Ar s2
+are identical.
+.It Ar s1 Cm != Ar s2
+True if the strings
+.Ar s1
+and
+.Ar s2
+are not identical.
+.It Ar s1 Cm < Ar s2
+True if string
+.Ar s1
+comes before
+.Ar s2
+based on the binary value of their characters.
+.It Ar s1 Cm > Ar s2
+True if string
+.Ar s1
+comes after
+.Ar s2
+based on the binary value of their characters.
+.It Ar n1 Fl eq Ar n2
+True if the integers
+.Ar n1
+and
+.Ar n2
+are algebraically
+equal.
+.It Ar n1 Fl ne Ar n2
+True if the integers
+.Ar n1
+and
+.Ar n2
+are not
+algebraically equal.
+.It Ar n1 Fl gt Ar n2
+True if the integer
+.Ar n1
+is algebraically
+greater than the integer
+.Ar n2 .
+.It Ar n1 Fl ge Ar n2
+True if the integer
+.Ar n1
+is algebraically
+greater than or equal to the integer
+.Ar n2 .
+.It Ar n1 Fl lt Ar n2
+True if the integer
+.Ar n1
+is algebraically less
+than the integer
+.Ar n2 .
+.It Ar n1 Fl le Ar n2
+True if the integer
+.Ar n1
+is algebraically less
+than or equal to the integer
+.Ar n2 .
+.El
+.Pp
+If
+.Ar file
+is a symbolic link,
+.Nm
+will fully dereference it and then evaluate the expression
+against the file referenced, except for the
+.Fl h
+and
+.Fl L
+primaries.
+.Pp
+These primaries can be combined with the following operators:
+.Bl -tag -width Ar
+.It Cm \&! Ar expression
+True if
+.Ar expression
+is false.
+.It Ar expression1 Fl a Ar expression2
+True if both
+.Ar expression1
+and
+.Ar expression2
+are true.
+.It Ar expression1 Fl o Ar expression2
+True if either
+.Ar expression1
+or
+.Ar expression2
+are true.
+.It Cm \&( Ar expression Cm \&)
+True if expression is true.
+.El
+.Pp
+The
+.Fl a
+operator has higher precedence than the
+.Fl o
+operator.
+.Pp
+Some shells may provide a builtin
+.Nm
+command which is similar or identical to this utility.
+Consult the
+.Xr builtin 1
+manual page.
+.Sh GRAMMAR AMBIGUITY
+The
+.Nm
+grammar is inherently ambiguous.
+In order to assure a degree of consistency,
+the cases described in the
+.St -p1003.2 ,
+section D11.2/4.62.4, standard
+are evaluated consistently according to the rules specified in the
+standards document.
+All other cases are subject to the ambiguity in the
+command semantics.
+.Pp
+In particular, only expressions containing
+.Fl a ,
+.Fl o ,
+.Cm \&(
+or
+.Cm \&)
+can be ambiguous.
+.Sh EXIT STATUS
+The
+.Nm
+utility exits with one of the following values:
+.Bl -tag -width indent
+.It 0
+expression evaluated to true.
+.It 1
+expression evaluated to false or expression was
+missing.
+.It >1
+An error occurred.
+.El
+.Sh EXAMPLES
+Implement
+.Li test FILE1 -nt FILE2
+using only
+.Tn POSIX
+functionality:
+.Pp
+.Dl test -n \&"$(find -L -- FILE1 -prune -newer FILE2 2>/dev/null)\&"
+.Pp
+This can be modified using non-standard
+.Xr find 1
+primaries like
+.Cm -newerca
+to compare other timestamps.
+.Sh COMPATIBILITY
+For compatibility with some other implementations,
+the
+.Cm =
+primary can be substituted with
+.Cm ==
+with the same meaning.
+.Sh SEE ALSO
+.Xr builtin 1 ,
+.Xr expr 1 ,
+.Xr find 1 ,
+.Xr sh 1 ,
+.Xr stat 1 ,
+.Xr symlink 7
+.Sh STANDARDS
+The
+.Nm
+utility implements a superset of the
+.St -p1003.2
+specification.
+The primaries
+.Cm < ,
+.Cm == ,
+.Cm > ,
+.Fl ef ,
+.Fl nt ,
+.Fl ot ,
+.Fl G ,
+and
+.Fl O
+are extensions.
+.Sh HISTORY
+A
+.Nm
+utility appeared in
+.At v7 .
+.Sh BUGS
+Both sides are always evaluated in
+.Fl a
+and
+.Fl o .
+For instance, the writable status of
+.Pa file
+will be tested by the following command even though the former expression
+indicated false, which results in a gratuitous access to the file system:
+.Dl "[ -z abc -a -w file ]"
+To avoid this, write
+.Dl "[ -z abc ] && [ -w file ]"
diff --git a/bin/1sh/1sh.1 b/bin/1sh/1sh.1
new file mode 100644
index 00000000..aa906bca
--- /dev/null
+++ b/bin/1sh/1sh.1
@@ -0,0 +1,2917 @@
+.\"-
+.\" Copyright (c) 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" Kenneth Almquist.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"	from: @(#)sh.1	8.6 (Berkeley) 5/4/95
+.\" $FreeBSD: releng/12.1/bin/sh/sh.1 345487 2019-03-24 22:10:26Z jilles $
+.\"
+.Dd March  9, 2020
+.Dt 1SH 1
+.Os
+.Sh NAME
+.Nm 1sh
+.Nd command interpreter (shell)
+.Sh SYNOPSIS
+.Nm
+.Op Fl /+abCEefhIimnPpTuVvx
+.Op Fl /+o Ar longname
+.Oo
+.Ar script
+.Op Ar arg ...
+.Oc
+.Nm
+.Op Fl /+abCEefhIimnPpTuVvx
+.Op Fl /+o Ar longname
+.Fl c Ar string
+.Oo
+.Ar name
+.Op Ar arg ...
+.Oc
+.Nm
+.Op Fl /+abCEefhIimnPpTuVvx
+.Op Fl /+o Ar longname
+.Fl s
+.Op Ar arg ...
+.Sh DESCRIPTION
+The
+.Nm
+utility is a command interpreter.
+The current version of
+.Nm
+is close to the
+.St -p1003.1
+specification for the shell.
+It only supports features
+designated by POSIX,
+plus a few Berkeley extensions.
+This man page is not intended to be a tutorial nor a complete
+specification of the shell.
+.Ss Overview
+The shell is a command that reads lines from
+either a file or the terminal, interprets them, and
+generally executes other commands.
+It is the program that is started when a user logs into the system,
+although a user can select a different shell with the
+.Xr chsh 1
+command.
+The shell
+implements a language that has flow control constructs,
+a macro facility that provides a variety of features in
+addition to data storage, along with built-in history and line
+editing capabilities.
+It incorporates many features to
+aid interactive use and has the advantage that the interpretative
+language is common to both interactive and non-interactive
+use (shell scripts).
+That is, commands can be typed directly
+to the running shell or can be put into a file,
+which can be executed directly by the shell.
+.Ss Invocation
+.\"
+.\" XXX This next sentence is incredibly confusing.
+.\"
+If no arguments are present and if the standard input of the shell
+is connected to a terminal
+(or if the
+.Fl i
+option is set),
+the shell is considered an interactive shell.
+An interactive shell
+generally prompts before each command and handles programming
+and command errors differently (as described below).
+When first starting, the shell inspects argument 0, and
+if it begins with a dash
+.Pq Ql - ,
+the shell is also considered a login shell.
+This is normally done automatically by the system
+when the user first logs in.
+A login shell first reads commands
+from the files
+.Pa /etc/profile
+and then
+.Pa .profile
+in a user's home directory,
+if they exist.
+If the environment variable
+.Ev ENV
+is set on entry to a shell, or is set in the
+.Pa .profile
+of a login shell, the shell then subjects its value to parameter expansion
+and arithmetic expansion and reads commands from the named file.
+Therefore, a user should place commands that are to be executed only
+at login time in the
+.Pa .profile
+file, and commands that are executed for every shell inside the
+.Ev ENV
+file.
+The user can set the
+.Ev ENV
+variable to some file by placing the following line in the file
+.Pa .profile
+in the home directory,
+substituting for
+.Pa .shrc
+the filename desired:
+.Pp
+.Dl "ENV=$HOME/.shrc; export ENV"
+.Pp
+The first non-option argument specified on the command line
+will be treated as the
+name of a file from which to read commands (a shell script), and
+the remaining arguments are set as the positional parameters
+of the shell
+.Li ( $1 , $2 ,
+etc.).
+Otherwise, the shell reads commands
+from its standard input.
+.Pp
+Unlike older versions of
+.Nm
+the
+.Ev ENV
+script is only sourced on invocation of interactive shells.
+This
+closes a well-known, and sometimes easily exploitable security
+hole related to poorly thought out
+.Ev ENV
+scripts.
+.Ss Argument List Processing
+All of the single letter options to
+.Nm
+have a corresponding long name,
+with the exception of
+.Fl c
+and
+.Fl /+o .
+These long names are provided next to the single letter options
+in the descriptions below.
+The long name for an option may be specified as an argument to the
+.Fl /+o
+option of
+.Nm .
+Once the shell is running,
+the long name for an option may be specified as an argument to the
+.Fl /+o
+option of the
+.Ic set
+built-in command
+(described later in the section called
+.Sx Built-in Commands ) .
+Introducing an option with a dash
+.Pq Ql -
+enables the option,
+while using a plus
+.Pq Ql +
+disables the option.
+A
+.Dq Li --
+or plain
+.Ql -
+will stop option processing and will force the remaining
+words on the command line to be treated as arguments.
+The
+.Fl /+o
+and
+.Fl c
+options do not have long names.
+They take arguments and are described after the single letter options.
+.Bl -tag -width indent
+.It Fl a Li allexport
+Flag variables for export when assignments are made to them.
+.It Fl b Li notify
+Enable asynchronous notification of background job
+completion.
+(UNIMPLEMENTED)
+.It Fl C Li noclobber
+Do not overwrite existing files with
+.Ql > .
+.It Fl E Li emacs
+Enable the built-in
+.Xr emacs 1
+command line editor (disables the
+.Fl V
+option if it has been set;
+set automatically when interactive on terminals).
+.It Fl e Li errexit
+Exit immediately if any untested command fails in non-interactive mode.
+The exit status of a command is considered to be
+explicitly tested if the command is part of the list used to control
+an
+.Ic if , elif , while ,
+or
+.Ic until ;
+if the command is the left
+hand operand of an
+.Dq Li &&
+or
+.Dq Li ||
+operator; or if the command is a pipeline preceded by the
+.Ic !\&
+keyword.
+If a shell function is executed and its exit status is explicitly
+tested, all commands of the function are considered to be tested as
+well.
+.Pp
+It is recommended to check for failures explicitly
+instead of relying on
+.Fl e
+because it tends to behave in unexpected ways,
+particularly in larger scripts.
+.It Fl f Li noglob
+Disable pathname expansion.
+.It Fl h Li trackall
+A do-nothing option for POSIX compliance.
+.It Fl I Li ignoreeof
+Ignore
+.Dv EOF Ap s
+from input when in interactive mode.
+.It Fl i Li interactive
+Force the shell to behave interactively.
+.It Fl m Li monitor
+Turn on job control (set automatically when interactive).
+A new process group is created for each pipeline (called a job).
+It is possible to suspend jobs or to have them run in the foreground or
+in the background.
+In a non-interactive shell,
+this option can be set even if no terminal is available
+and is useful to place processes in separate process groups.
+.It Fl n Li noexec
+If not interactive, read commands but do not
+execute them.
+This is useful for checking the
+syntax of shell scripts.
+.It Fl P Li physical
+Change the default for the
+.Ic cd
+and
+.Ic pwd
+commands from
+.Fl L
+(logical directory layout)
+to
+.Fl P
+(physical directory layout).
+.It Fl p Li privileged
+Turn on privileged mode.
+This mode is enabled on startup
+if either the effective user or group ID is not equal to the
+real user or group ID.
+Turning this mode off sets the
+effective user and group IDs to the real user and group IDs.
+When this mode is enabled for interactive shells, the file
+.Pa /etc/suid_profile
+is sourced instead of
+.Pa ~/.profile
+after
+.Pa /etc/profile
+is sourced, and the contents of the
+.Ev ENV
+variable are ignored.
+.It Fl s Li stdin
+Read commands from standard input (set automatically
+if no file arguments are present).
+This option has
+no effect when set after the shell has already started
+running (i.e., when set with the
+.Ic set
+command).
+.It Fl T Li trapsasync
+When waiting for a child, execute traps immediately.
+If this option is not set,
+traps are executed after the child exits,
+as specified in
+.St -p1003.2 .
+This nonstandard option is useful for putting guarding shells around
+children that block signals.
+The surrounding shell may kill the child
+or it may just return control to the tty and leave the child alone,
+like this:
+.Bd -literal -offset indent
+1sh -T -c "trap 'exit 1' 2 ; some-blocking-program"
+.Ed
+.It Fl u Li nounset
+Write a message to standard error when attempting
+to expand a variable, a positional parameter or
+the special parameter
+.Va \&!
+that is not set, and if the
+shell is not interactive, exit immediately.
+.It Fl V Li vi
+Enable the built-in
+.Xr vi 1
+command line editor (disables
+.Fl E
+if it has been set).
+.It Fl v Li verbose
+The shell writes its input to standard error
+as it is read.
+Useful for debugging.
+.It Fl x Li xtrace
+Write each command
+(preceded by the value of the
+.Va PS4
+variable subjected to parameter expansion and arithmetic expansion)
+to standard error before it is executed.
+Useful for debugging.
+.It Li nolog
+Another do-nothing option for POSIX compliance.
+It only has a long name.
+.It Li pipefail
+Change the exit status of a pipeline to the last non-zero exit status of
+any command in the pipeline, if any.
+Since an exit due to
+.Dv SIGPIPE
+counts as a non-zero exit status,
+this option may cause non-zero exit status for successful pipelines
+if a command such as
+.Xr head 1
+in the pipeline terminates with status 0 without reading its
+input completely.
+This option only has a long name.
+.El
+.Pp
+The
+.Fl c
+option causes the commands to be read from the
+.Ar string
+operand instead of from the standard input.
+Keep in mind that this option only accepts a single string as its
+argument, hence multi-word strings must be quoted.
+.Pp
+The
+.Fl /+o
+option takes as its only argument the long name of an option
+to be enabled or disabled.
+For example, the following two invocations of
+.Nm
+both enable the built-in
+.Xr emacs 1
+command line editor:
+.Bd -literal -offset indent
+set -E
+set -o emacs
+.Ed
+.Pp
+If used without an argument, the
+.Fl o
+option displays the current option settings in a human-readable format.
+If
+.Cm +o
+is used without an argument, the current option settings are output
+in a format suitable for re-input into the shell.
+.Ss Lexical Structure
+The shell reads input in terms of lines from a file and breaks
+it up into words at whitespace (blanks and tabs), and at
+certain sequences of
+characters called
+.Dq operators ,
+which are special to the shell.
+There are two types of operators: control operators and
+redirection operators (their meaning is discussed later).
+The following is a list of valid operators:
+.Bl -tag -width indent
+.It Control operators:
+.Bl -column "XXX" "XXX" "XXX" "XXX" "XXX" -offset center -compact
+.It Li & Ta Li && Ta Li \&( Ta Li \&) Ta Li \en
+.It Li ;; Ta Li ;& Ta Li \&; Ta Li \&| Ta Li ||
+.El
+.It Redirection operators:
+.Bl -column "XXX" "XXX" "XXX" "XXX" "XXX" -offset center -compact
+.It Li < Ta Li > Ta Li << Ta Li >> Ta Li <>
+.It Li <& Ta Li >& Ta Li <<- Ta Li >| Ta \&
+.El
+.El
+.Pp
+The character
+.Ql #
+introduces a comment if used at the beginning of a word.
+The word starting with
+.Ql #
+and the rest of the line are ignored.
+.Pp
+ASCII
+.Dv NUL
+characters (character code 0) are not allowed in shell input.
+.Ss Quoting
+Quoting is used to remove the special meaning of certain characters
+or words to the shell, such as operators, whitespace, keywords,
+or alias names.
+.Pp
+There are four types of quoting: matched single quotes,
+dollar-single quotes,
+matched double quotes, and backslash.
+.Bl -tag -width indent
+.It Single Quotes
+Enclosing characters in single quotes preserves the literal
+meaning of all the characters (except single quotes, making
+it impossible to put single-quotes in a single-quoted string).
+.It Dollar-Single Quotes
+Enclosing characters between
+.Li $'
+and
+.Li '
+preserves the literal meaning of all characters
+except backslashes and single quotes.
+A backslash introduces a C-style escape sequence:
+.Bl -tag -width xUnnnnnnnn
+.It \ea
+Alert (ring the terminal bell)
+.It \eb
+Backspace
+.It \ec Ns Ar c
+The control character denoted by
+.Li ^ Ns Ar c
+in
+.Xr stty 1 .
+If
+.Ar c
+is a backslash, it must be doubled.
+.It \ee
+The ESC character (ASCII 0x1b)
+.It \ef
+Formfeed
+.It \en
+Newline
+.It \er
+Carriage return
+.It \et
+Horizontal tab
+.It \ev
+Vertical tab
+.It \e\e
+Literal backslash
+.It \e\&'
+Literal single-quote
+.It \e\&"
+Literal double-quote
+.It \e Ns Ar nnn
+The byte whose octal value is
+.Ar nnn
+(one to three digits)
+.It \ex Ns Ar nn
+The byte whose hexadecimal value is
+.Ar nn
+(one or more digits only the last two of which are used)
+.It \eu Ns Ar nnnn
+The Unicode code point
+.Ar nnnn
+(four hexadecimal digits)
+.It \eU Ns Ar nnnnnnnn
+The Unicode code point
+.Ar nnnnnnnn
+(eight hexadecimal digits)
+.El
+.Pp
+The sequences for Unicode code points are currently only useful with
+UTF-8 locales.
+They reject code point 0 and UTF-16 surrogates.
+.Pp
+If an escape sequence would produce a byte with value 0,
+that byte and the rest of the string until the matching single-quote
+are ignored.
+.Pp
+Any other string starting with a backslash is an error.
+.It Double Quotes
+Enclosing characters within double quotes preserves the literal
+meaning of all characters except dollar sign
+.Pq Ql $ ,
+backquote
+.Pq Ql ` ,
+and backslash
+.Pq Ql \e .
+The backslash inside double quotes is historically weird.
+It remains literal unless it precedes the following characters,
+which it serves to quote:
+.Pp
+.Bl -column "XXX" "XXX" "XXX" "XXX" "XXX" -offset center -compact
+.It Li $ Ta Li ` Ta Li \&" Ta Li \e Ta Li \en
+.El
+.It Backslash
+A backslash preserves the literal meaning of the following
+character, with the exception of the newline character
+.Pq Ql \en .
+A backslash preceding a newline is treated as a line continuation.
+.El
+.Ss Keywords
+Keywords or reserved words are words that have special meaning to the
+shell and are recognized at the beginning of a line and
+after a control operator.
+The following are keywords:
+.Bl -column "doneXX" "elifXX" "elseXX" "untilXX" "whileX" -offset center
+.It Li \&! Ta { Ta } Ta Ic case Ta Ic do
+.It Ic done Ta Ic elif Ta Ic else Ta Ic esac Ta Ic fi
+.It Ic for Ta Ic if Ta Ic then Ta Ic until Ta Ic while
+.El
+.Ss Aliases
+An alias is a name and corresponding value set using the
+.Ic alias
+built-in command.
+Wherever the command word of a simple command may occur,
+and after checking for keywords if a keyword may occur, the shell
+checks the word to see if it matches an alias.
+If it does, it replaces it in the input stream with its value.
+For example, if there is an alias called
+.Dq Li lf
+with the value
+.Dq Li "ls -F" ,
+then the input
+.Pp
+.Dl "lf foobar"
+.Pp
+would become
+.Pp
+.Dl "ls -F foobar"
+.Pp
+Aliases are also recognized after an alias
+whose value ends with a space or tab.
+For example, if there is also an alias called
+.Dq Li nohup
+with the value
+.Dq Li "nohup " ,
+then the input
+.Pp
+.Dl "nohup lf foobar"
+.Pp
+would become
+.Pp
+.Dl "nohup ls -F foobar"
+.Pp
+Aliases provide a convenient way for naive users to
+create shorthands for commands without having to learn how
+to create functions with arguments.
+Using aliases in scripts is discouraged
+because the command that defines them must be executed
+before the code that uses them is parsed.
+This is fragile and not portable.
+.Pp
+An alias name may be escaped in a command line, so that it is not
+replaced by its alias value, by using quoting characters within or
+adjacent to the alias name.
+This is most often done by prefixing
+an alias name with a backslash to execute a function, built-in, or
+normal program with the same name.
+See the
+.Sx Quoting
+subsection.
+.Ss Commands
+The shell interprets the words it reads according to a
+language, the specification of which is outside the scope
+of this man page (refer to the BNF in the
+.St -p1003.2
+document).
+Essentially though, a line is read and if
+the first word of the line (or after a control operator)
+is not a keyword, then the shell has recognized a
+simple command.
+Otherwise, a complex command or some
+other special construct may have been recognized.
+.Ss Simple Commands
+If a simple command has been recognized, the shell performs
+the following actions:
+.Bl -enum
+.It
+Leading words of the form
+.Dq Li name=value
+are stripped off and assigned to the environment of
+the simple command
+(they do not affect expansions).
+Redirection operators and
+their arguments (as described below) are stripped
+off and saved for processing.
+.It
+The remaining words are expanded as described in
+the section called
+.Sx Word Expansions ,
+and the first remaining word is considered the command
+name and the command is located.
+The remaining
+words are considered the arguments of the command.
+If no command name resulted, then the
+.Dq Li name=value
+variable assignments recognized in 1) affect the
+current shell.
+.It
+Redirections are performed as described in
+the next section.
+.El
+.Ss Redirections
+Redirections are used to change where a command reads its input
+or sends its output.
+In general, redirections open, close, or
+duplicate an existing reference to a file.
+The overall format
+used for redirection is:
+.Pp
+.D1 Oo Ar n Oc Ar redir-op file
+.Pp
+The
+.Ar redir-op
+is one of the redirection operators mentioned
+previously.
+The following gives some examples of how these
+operators can be used.
+Note that stdin and stdout are commonly used abbreviations
+for standard input and standard output respectively.
+.Bl -tag -width "1234567890XX" -offset indent
+.It Oo Ar n Oc Ns Li > Ar file
+redirect stdout (or file descriptor
+.Ar n )
+to
+.Ar file
+.It Oo Ar n Oc Ns Li >| Ar file
+same as above, but override the
+.Fl C
+option
+.It Oo Ar n Oc Ns Li >> Ar file
+append stdout (or file descriptor
+.Ar n )
+to
+.Ar file
+.It Oo Ar n Oc Ns Li < Ar file
+redirect stdin (or file descriptor
+.Ar n )
+from
+.Ar file
+.It Oo Ar n Oc Ns Li <> Ar file
+redirect stdin (or file descriptor
+.Ar n )
+to and from
+.Ar file
+.It Oo Ar n1 Oc Ns Li <& Ns Ar n2
+duplicate stdin (or file descriptor
+.Ar n1 )
+from file descriptor
+.Ar n2
+.It Oo Ar n Oc Ns Li <&-
+close stdin (or file descriptor
+.Ar n )
+.It Oo Ar n1 Oc Ns Li >& Ns Ar n2
+duplicate stdout (or file descriptor
+.Ar n1 )
+to file descriptor
+.Ar n2
+.It Oo Ar n Oc Ns Li >&-
+close stdout (or file descriptor
+.Ar n )
+.El
+.Pp
+The following redirection is often called a
+.Dq here-document .
+.Bd -unfilled -offset indent
+.Oo Ar n Oc Ns Li << Ar delimiter
+.Ar here-doc-text
+.Ar ...
+.Ar delimiter
+.Ed
+.Pp
+All the text on successive lines up to the delimiter is
+saved away and made available to the command on standard
+input, or file descriptor
+.Ar n
+if it is specified.
+If the
+.Ar delimiter
+as specified on the initial line is quoted, then the
+.Ar here-doc-text
+is treated literally, otherwise the text is subjected to
+parameter expansion, command substitution, and arithmetic
+expansion (as described in the section on
+.Sx Word Expansions ) .
+If the operator is
+.Dq Li <<-
+instead of
+.Dq Li << ,
+then leading tabs
+in the
+.Ar here-doc-text
+are stripped.
+.Ss Search and Execution
+There are three types of commands: shell functions,
+built-in commands, and normal programs.
+The command is searched for (by name) in that order.
+The three types of commands are all executed in a different way.
+.Pp
+When a shell function is executed, all of the shell positional
+parameters (except
+.Li $0 ,
+which remains unchanged) are
+set to the arguments of the shell function.
+The variables which are explicitly placed in the environment of
+the command (by placing assignments to them before the
+function name) are made local to the function and are set
+to the values given.
+Then the command given in the function definition is executed.
+The positional parameters are restored to their original values
+when the command completes.
+This all occurs within the current shell.
+.Pp
+Shell built-in commands are executed internally to the shell, without
+spawning a new process.
+There are two kinds of built-in commands: regular and special.
+Assignments before special builtins persist after they finish
+executing and assignment errors, redirection errors and certain
+operand errors cause a script to be aborted.
+Special builtins cannot be overridden with a function.
+Both regular and special builtins can affect the shell in ways
+normal programs cannot.
+.Pp
+Otherwise, if the command name does not match a function
+or built-in command, the command is searched for as a normal
+program in the file system (as described in the next section).
+When a normal program is executed, the shell runs the program,
+passing the arguments and the environment to the program.
+If the program is not a normal executable file
+(i.e., if it does not begin with the
+.Dq "magic number"
+whose ASCII representation is
+.Dq Li #! ,
+resulting in an
+.Er ENOEXEC
+return value from
+.Xr execve 2 )
+but appears to be a text file,
+the shell will run a new instance of
+.Nm
+to interpret it.
+.Pp
+Note that previous versions of this document
+and the source code itself misleadingly and sporadically
+refer to a shell script without a magic number
+as a
+.Dq "shell procedure" .
+.Ss Path Search
+When locating a command, the shell first looks to see if
+it has a shell function by that name.
+Then it looks for a
+built-in command by that name.
+If a built-in command is not found,
+one of two things happen:
+.Bl -enum
+.It
+Command names containing a slash are simply executed without
+performing any searches.
+.It
+The shell searches each entry in the
+.Va PATH
+variable
+in turn for the command.
+The value of the
+.Va PATH
+variable should be a series of
+entries separated by colons.
+Each entry consists of a
+directory name.
+The current directory
+may be indicated implicitly by an empty directory name,
+or explicitly by a single period.
+.El
+.Ss Command Exit Status
+Each command has an exit status that can influence the behavior
+of other shell commands.
+The paradigm is that a command exits
+with zero for normal or success, and non-zero for failure,
+error, or a false indication.
+The man page for each command
+should indicate the various exit codes and what they mean.
+Additionally, the built-in commands return exit codes, as does
+an executed shell function.
+.Pp
+If a command is terminated by a signal, its exit status is greater than 128.
+The signal name can be found by passing the exit status to
+.Li kill -l .
+.Pp
+If there is no command word,
+the exit status is the exit status of the last command substitution executed,
+or zero if the command does not contain any command substitutions.
+.Ss Complex Commands
+Complex commands are combinations of simple commands
+with control operators or keywords, together creating a larger complex
+command.
+More generally, a command is one of the following:
+.Bl -item -offset indent
+.It
+simple command
+.It
+pipeline
+.It
+list or compound-list
+.It
+compound command
+.It
+function definition
+.El
+.Pp
+Unless otherwise stated, the exit status of a command is
+that of the last simple command executed by the command,
+or zero if no simple command was executed.
+.Ss Pipelines
+A pipeline is a sequence of one or more commands separated
+by the control operator
+.Ql \&| .
+The standard output of all but
+the last command is connected to the standard input
+of the next command.
+The standard output of the last
+command is inherited from the shell, as usual.
+.Pp
+The format for a pipeline is:
+.Pp
+.D1 Oo Li \&! Oc Ar command1 Op Li \&| Ar command2 ...
+.Pp
+The standard output of
+.Ar command1
+is connected to the standard input of
+.Ar command2 .
+The standard input, standard output, or
+both of a command is considered to be assigned by the
+pipeline before any redirection specified by redirection
+operators that are part of the command.
+.Pp
+Note that unlike some other shells,
+.Nm
+executes each process in a pipeline with more than one command
+in a subshell environment and as a child of the
+.Nm
+process.
+.Pp
+If the pipeline is not in the background (discussed later),
+the shell waits for all commands to complete.
+.Pp
+If the keyword
+.Ic !\&
+does not precede the pipeline, the
+exit status is the exit status of the last command specified
+in the pipeline if the
+.Cm pipefail
+option is not set or all commands returned zero,
+or the last non-zero exit status of any command in the pipeline otherwise.
+Otherwise, the exit status is the logical
+NOT of that exit status.
+That is, if
+that status is zero, the exit status is 1; if
+that status is greater than zero, the exit status
+is zero.
+.Pp
+Because pipeline assignment of standard input or standard
+output or both takes place before redirection, it can be
+modified by redirection.
+For example:
+.Pp
+.Dl "command1 2>&1 | command2"
+.Pp
+sends both the standard output and standard error of
+.Ar command1
+to the standard input of
+.Ar command2 .
+.Pp
+A
+.Ql \&;
+or newline terminator causes the preceding
+AND-OR-list
+(described below in the section called
+.Sx Short-Circuit List Operators )
+to be executed sequentially;
+an
+.Ql &
+causes asynchronous execution of the preceding AND-OR-list.
+.Ss Background Commands (&)
+If a command is terminated by the control operator ampersand
+.Pq Ql & ,
+the shell executes the command in a subshell environment (see
+.Sx Grouping Commands Together
+below) and asynchronously;
+the shell does not wait for the command to finish
+before executing the next command.
+.Pp
+The format for running a command in background is:
+.Pp
+.D1 Ar command1 Li & Op Ar command2 Li & Ar ...
+.Pp
+If the shell is not interactive, the standard input of an
+asynchronous command is set to
+.Pa /dev/null .
+.Pp
+The exit status is zero.
+.Ss Lists (Generally Speaking)
+A list is a sequence of zero or more commands separated by
+newlines, semicolons, or ampersands,
+and optionally terminated by one of these three characters.
+The commands in a
+list are executed in the order they are written.
+If command is followed by an ampersand, the shell starts the
+command and immediately proceeds onto the next command;
+otherwise it waits for the command to terminate before
+proceeding to the next one.
+.Ss Short-Circuit List Operators
+.Dq Li &&
+and
+.Dq Li ||
+are AND-OR list operators.
+.Dq Li &&
+executes the first command, and then executes the second command
+if the exit status of the first command is zero.
+.Dq Li ||
+is similar, but executes the second command if the exit
+status of the first command is nonzero.
+.Dq Li &&
+and
+.Dq Li ||
+both have the same priority.
+.Ss Flow-Control Constructs (if, while, for, case)
+The syntax of the
+.Ic if
+command is:
+.Bd -unfilled -offset indent -compact
+.Ic if Ar list
+.Ic then Ar list
+.Oo Ic elif Ar list
+.Ic then Ar list Oc Ar ...
+.Op Ic else Ar list
+.Ic fi
+.Ed
+.Pp
+The exit status is that of selected
+.Ic then
+or
+.Ic else
+list,
+or zero if no list was selected.
+.Pp
+The syntax of the
+.Ic while
+command is:
+.Bd -unfilled -offset indent -compact
+.Ic while Ar list
+.Ic do Ar list
+.Ic done
+.Ed
+.Pp
+The two lists are executed repeatedly while the exit status of the
+first list is zero.
+The
+.Ic until
+command is similar, but has the word
+.Ic until
+in place of
+.Ic while ,
+which causes it to
+repeat until the exit status of the first list is zero.
+.Pp
+The exit status is that of the last execution of the second list,
+or zero if it was never executed.
+.Pp
+The syntax of the
+.Ic for
+command is:
+.Bd -unfilled -offset indent -compact
+.Ic for Ar variable Op Ic in Ar word ...
+.Ic do Ar list
+.Ic done
+.Ed
+.Pp
+If
+.Ic in
+and the following words are omitted,
+.Ic in Li \&"$@\&"
+is used instead.
+The words are expanded, and then the list is executed
+repeatedly with the variable set to each word in turn.
+The
+.Ic do
+and
+.Ic done
+commands may be replaced with
+.Ql {
+and
+.Ql } .
+.Pp
+The syntax of the
+.Ic break
+and
+.Ic continue
+commands is:
+.D1 Ic break Op Ar num
+.D1 Ic continue Op Ar num
+.Pp
+The
+.Ic break
+command terminates the
+.Ar num
+innermost
+.Ic for
+or
+.Ic while
+loops.
+The
+.Ic continue
+command continues with the next iteration of the innermost loop.
+These are implemented as special built-in commands.
+.Pp
+The syntax of the
+.Ic case
+command is:
+.Bd -unfilled -offset indent -compact
+.Ic case Ar word Ic in
+.Ar pattern ) Ar list Li ;;
+.Ar ...
+.Ic esac
+.Ed
+.Pp
+The pattern can actually be one or more patterns
+(see
+.Sx Shell Patterns
+described later),
+separated by
+.Ql \&|
+characters.
+Tilde expansion, parameter expansion, command substitution,
+arithmetic expansion and quote removal are applied to the word.
+Then, each pattern is expanded in turn using tilde expansion,
+parameter expansion, command substitution and arithmetic expansion and
+the expanded form of the word is checked against it.
+If a match is found, the corresponding list is executed.
+If the selected list is terminated by the control operator
+.Ql ;&
+instead of
+.Ql ;; ,
+execution continues with the next list,
+continuing until a list terminated with
+.Ql ;;
+or the end of the
+.Ic case
+command.
+.Ss Grouping Commands Together
+Commands may be grouped by writing either
+.Pp
+.Sm off
+.Bd -literal -offset -ident
+.Po Ar list Pc
+.Ed
+.Sm on
+.Pp
+or
+.Bd -literal -offset -ident
+.No { Ar list ; }
+.Ed
+.Pp
+The first form executes the commands in a subshell environment.
+A subshell environment has its own copy of:
+.Bl -enum
+.It
+The current working directory as set by
+.Ic cd .
+.It
+The file creation mask as set by
+.Ic umask .
+.It
+Resource limits as set by
+.Ic ulimit .
+.It
+References to open files.
+.It
+Traps as set by
+.Ic trap .
+.It
+Known jobs.
+.It
+Positional parameters and variables.
+.It
+Shell options.
+.It
+Shell functions.
+.It
+Shell aliases.
+.El
+.Pp
+These are copied from the parent shell environment,
+except that trapped (but not ignored) signals are reset to the default action
+and known jobs are cleared.
+Any changes do not affect the parent shell environment.
+.Pp
+A subshell environment may be implemented as a child process or differently.
+If job control is enabled in an interactive shell,
+commands grouped in parentheses can be suspended and continued as a unit.
+.Pp
+For compatibility with other shells,
+two open parentheses in sequence should be separated by whitespace.
+.Pp
+The second form never forks another shell,
+so it is slightly more efficient.
+Grouping commands together this way allows the user to
+redirect their output as though they were one program:
+.Bd -literal -offset indent
+{ echo -n "hello"; echo " world"; } > greeting
+.Ed
+.Ss Functions
+The syntax of a function definition is
+.Pp
+.D1 Ar name Li \&( \&) Ar command
+.Pp
+A function definition is an executable statement; when
+executed it installs a function named
+.Ar name
+and returns an
+exit status of zero.
+The
+.Ar command
+is normally a list
+enclosed between
+.Ql {
+and
+.Ql } .
+.Pp
+Variables may be declared to be local to a function by
+using the
+.Ic local
+command.
+This should appear as the first statement of a function,
+and the syntax is:
+.Pp
+.D1 Ic local Oo Ar variable ... Oc Op Fl
+.Pp
+The
+.Ic local
+command is implemented as a built-in command.
+The exit status is zero
+unless the command is not in a function or a variable name is invalid.
+.Pp
+When a variable is made local, it inherits the initial
+value and exported and readonly flags from the variable
+with the same name in the surrounding scope, if there is
+one.
+Otherwise, the variable is initially unset.
+The shell
+uses dynamic scoping, so that if the variable
+.Va x
+is made local to function
+.Em f ,
+which then calls function
+.Em g ,
+references to the variable
+.Va x
+made inside
+.Em g
+will refer to the variable
+.Va x
+declared inside
+.Em f ,
+not to the global variable named
+.Va x .
+.Pp
+The only special parameter that can be made local is
+.Ql - .
+Making
+.Ql -
+local causes any shell options
+(including those that only have long names)
+that are
+changed via the
+.Ic set
+command inside the function to be
+restored to their original values when the function
+returns.
+.Pp
+The syntax of the
+.Ic return
+command is
+.Pp
+.D1 Ic return Op Ar exitstatus
+.Pp
+It terminates the current executional scope, returning from the closest
+nested function or sourced script;
+if no function or sourced script is being executed,
+it exits the shell instance.
+The
+.Ic return
+command is implemented as a special built-in command.
+.Ss Variables and Parameters
+The shell maintains a set of parameters.
+A parameter
+denoted by a name
+(consisting solely
+of alphabetics, numerics, and underscores,
+and starting with an alphabetic or an underscore)
+is called a variable.
+When starting up,
+the shell turns all environment variables with valid names into shell
+variables.
+New variables can be set using the form
+.Pp
+.D1 Ar name Ns = Ns Ar value
+.Pp
+A parameter can also be denoted by a number
+or a special character as explained below.
+.Pp
+Assignments are expanded differently from other words:
+tilde expansion is also performed after the equals sign and after any colon
+and usernames are also terminated by colons,
+and field splitting and pathname expansion are not performed.
+.Pp
+This special expansion applies not only to assignments that form a simple
+command by themselves or precede a command word,
+but also to words passed to the
+.Ic export ,
+.Ic local
+or
+.Ic readonly
+built-in commands that have this form.
+For this, the builtin's name must be literal
+(not the result of an expansion)
+and may optionally be preceded by one or more literal instances of
+.Ic command
+without options.
+.Ss Positional Parameters
+A positional parameter is a parameter denoted by a number greater than zero.
+The shell sets these initially to the values of its command line
+arguments that follow the name of the shell script.
+The
+.Ic set
+built-in command can also be used to set or reset them.
+.Ss Special Parameters
+Special parameters are parameters denoted by a single special character
+or the digit zero.
+They are shown in the following list, exactly as they would appear in input
+typed by the user or in the source of a shell script.
+.Bl -hang
+.It Li $*
+Expands to the positional parameters, starting from one.
+When
+the expansion occurs within a double-quoted string
+it expands to a single field with the value of each parameter
+separated by the first character of the
+.Va IFS
+variable,
+or by a space if
+.Va IFS
+is unset.
+.It Li $@
+Expands to the positional parameters, starting from one.
+When
+the expansion occurs within double-quotes, each positional
+parameter expands as a separate argument.
+If there are no positional parameters, the
+expansion of
+.Li @
+generates zero arguments, even when
+.Li @
+is double-quoted.
+What this basically means, for example, is
+if
+.Li $1
+is
+.Dq Li abc
+and
+.Li $2
+is
+.Dq Li "def ghi" ,
+then
+.Li \&"$@\&"
+expands to
+the two arguments:
+.Bd -literal -offset indent
+"abc"   "def ghi"
+.Ed
+.It Li $#
+Expands to the number of positional parameters.
+.It Li $?
+Expands to the exit status of the most recent pipeline.
+.It Li $-
+(hyphen) Expands to the current option flags (the single-letter
+option names concatenated into a string) as specified on
+invocation, by the
+.Ic set
+built-in command, or implicitly
+by the shell.
+.It Li $$
+Expands to the process ID of the invoked shell.
+A subshell
+retains the same value of
+.Va $
+as its parent.
+.It Li $!
+Expands to the process ID of the most recent background
+command executed from the current shell.
+For a
+pipeline, the process ID is that of the last command in the
+pipeline.
+If this parameter is referenced, the shell will remember
+the process ID and its exit status until the
+.Ic wait
+built-in command reports completion of the process.
+.It Li $0
+(zero) Expands to the name of the shell script if passed on the command line,
+the
+.Ar name
+operand if given (with
+.Fl c )
+or otherwise argument 0 passed to the shell.
+.El
+.Ss Special Variables
+The following variables are set by the shell or
+have special meaning to it:
+.Bl -tag -width ".Va HISTSIZE"
+.It Va CDPATH
+The search path used with the
+.Ic cd
+built-in.
+.It Va EDITOR
+The fallback editor used with the
+.Ic fc
+built-in.
+If not set, the default editor is
+.Xr ed 1 .
+.It Va FCEDIT
+The default editor used with the
+.Ic fc
+built-in.
+.It Va HISTFILE
+The path to the file in which command history is saved.
+History is loaded when
+.Va HISTFILE
+is set and saved on exit.
+.It Va HISTSIZE
+The number of previous commands that are accessible.
+.It Va HOME
+The user's home directory,
+used in tilde expansion and as a default directory for the
+.Ic cd
+built-in.
+.It Va IFS
+Input Field Separators.
+This is initialized at startup to
+.Aq space ,
+.Aq tab ,
+and
+.Aq newline
+in that order.
+This value also applies if
+.Va IFS
+is unset, but not if it is set to the empty string.
+See the
+.Sx White Space Splitting
+section for more details.
+.It Va LINENO
+The current line number in the script or function.
+.It Va MAIL
+The name of a mail file, that will be checked for the arrival of new
+mail.
+Overridden by
+.Va MAILPATH .
+.It Va MAILPATH
+A colon
+.Pq Ql \&:
+separated list of file names, for the shell to check for incoming
+mail.
+This variable overrides the
+.Va MAIL
+setting.
+There is a maximum of 10 mailboxes that can be monitored at once.
+.It Va OPTIND
+The index of the next argument to be processed by
+.Ic getopts .
+This is initialized to 1 at startup.
+.It Va PATH
+The default search path for executables.
+See the
+.Sx Path Search
+section for details.
+.It Va PPID
+The parent process ID of the invoked shell.
+This is set at startup
+unless this variable is in the environment.
+A later change of parent process ID is not reflected.
+A subshell retains the same value of
+.Va PPID .
+.It Va PS0
+The pre-prompt string,
+which is printed before each new prompt.
+.Va PS0
+may include any of the formatting sequences from
+.Va PS1 .
+.It Va PS1
+The primary prompt string, which defaults to
+.Dq Li "$ " ,
+unless you are the superuser, in which case it defaults to
+.Dq Li "# " .
+.Va PS1
+may include any of the following formatting sequences,
+which are replaced by the given information:
+.Bl -tag -width indent
+.It Li \eH
+This system's fully-qualified hostname (FQDN).
+.It Li \eh
+This system's hostname.
+.It Li \eW
+The final component of the current working directory.
+.It Li \ew
+The entire path of the current working directory.
+.It Li \e?
+Exit status if it is non-zero, empty string otherwise.
+.It Li \e$
+Superuser status.
+.Dq Li "$ "
+for normal users and
+.Dq Li "# "
+for superusers.
+.It Li \e\e
+A literal backslash.
+.El
+.It Va PS2
+The secondary prompt string, which defaults to
+.Dq Li "> " .
+.Va PS2
+may include any of the formatting sequences from
+.Va PS1 .
+.It Va PS4
+The prefix for the trace output (if
+.Fl x
+is active).
+The default is
+.Dq Li "+ " .
+.It Va RPS1
+The primary right prompt string.
+.Va RPS1
+may include any of the formatting sequences from
+.Va PS1 .
+.It Va RPS2
+The secondary right prompt string.
+.Va RPS2
+may include any of the formatting sequences from
+.Va PS1 .
+.El
+.Ss Word Expansions
+This clause describes the various expansions that are
+performed on words.
+Not all expansions are performed on
+every word, as explained later.
+.Pp
+Tilde expansions, parameter expansions, command substitutions,
+arithmetic expansions, and quote removals that occur within
+a single word expand to a single field.
+It is only field
+splitting or pathname expansion that can create multiple
+fields from a single word.
+The single exception to this rule is
+the expansion of the special parameter
+.Va @
+within double-quotes,
+as was described above.
+.Pp
+The order of word expansion is:
+.Bl -enum
+.It
+Tilde Expansion, Parameter Expansion, Command Substitution,
+Arithmetic Expansion (these all occur at the same time).
+.It
+Field Splitting is performed on fields generated by step (1)
+unless the
+.Va IFS
+variable is null.
+.It
+Pathname Expansion (unless the
+.Fl f
+option is in effect).
+.It
+Quote Removal.
+.El
+.Pp
+The
+.Ql $
+character is used to introduce parameter expansion, command
+substitution, or arithmetic expansion.
+.Ss Tilde Expansion (substituting a user's home directory)
+A word beginning with an unquoted tilde character
+.Pq Ql ~
+is
+subjected to tilde expansion.
+All the characters up to a slash
+.Pq Ql /
+or the end of the word are treated as a username
+and are replaced with the user's home directory.
+If the
+username is missing (as in
+.Pa ~/foobar ) ,
+the tilde is replaced with the value of the
+.Va HOME
+variable (the current user's home directory).
+.Ss Parameter Expansion
+The format for parameter expansion is as follows:
+.Pp
+.D1 Li ${ Ns Ar expression Ns Li }
+.Pp
+where
+.Ar expression
+consists of all characters until the matching
+.Ql } .
+Any
+.Ql }
+escaped by a backslash or within a single-quoted or double-quoted
+string, and characters in
+embedded arithmetic expansions, command substitutions, and variable
+expansions, are not examined in determining the matching
+.Ql } .
+If the variants with
+.Ql + ,
+.Ql - ,
+.Ql =
+or
+.Ql ?\&
+occur within a double-quoted string,
+as an extension there may be unquoted parts
+(via double-quotes inside the expansion);
+.Ql }
+within such parts are also not examined in determining the matching
+.Ql } .
+.Pp
+The simplest form for parameter expansion is:
+.Pp
+.D1 Li ${ Ns Ar parameter Ns Li }
+.Pp
+The value, if any, of
+.Ar parameter
+is substituted.
+.Pp
+The parameter name or symbol can be enclosed in braces, which are
+optional except for positional parameters with more than one digit or
+when parameter is followed by a character that could be interpreted as
+part of the name.
+If a parameter expansion occurs inside double-quotes:
+.Bl -enum
+.It
+Field splitting is not performed on the results of the
+expansion, with the exception of the special parameter
+.Va @ .
+.It
+Pathname expansion is not performed on the results of the
+expansion.
+.El
+.Pp
+In addition, a parameter expansion can be modified by using one of the
+following formats.
+.Bl -tag -width indent
+.It Li ${ Ns Ar parameter Ns Li :- Ns Ar word Ns Li }
+Use Default Values.
+If
+.Ar parameter
+is unset or null, the expansion of
+.Ar word
+is substituted; otherwise, the value of
+.Ar parameter
+is substituted.
+.It Li ${ Ns Ar parameter Ns Li := Ns Ar word Ns Li }
+Assign Default Values.
+If
+.Ar parameter
+is unset or null, the expansion of
+.Ar word
+is assigned to
+.Ar parameter .
+In all cases, the
+final value of
+.Ar parameter
+is substituted.
+Quoting inside
+.Ar word
+does not prevent field splitting or pathname expansion.
+Only variables, not positional
+parameters or special parameters, can be
+assigned in this way.
+.It Li ${ Ns Ar parameter Ns Li :? Ns Oo Ar word Oc Ns Li }
+Indicate Error if Null or Unset.
+If
+.Ar parameter
+is unset or null, the expansion of
+.Ar word
+(or a message indicating it is unset if
+.Ar word
+is omitted) is written to standard
+error and the shell exits with a nonzero
+exit status.
+Otherwise, the value of
+.Ar parameter
+is substituted.
+An
+interactive shell need not exit.
+.It Li ${ Ns Ar parameter Ns Li :+ Ns Ar word Ns Li }
+Use Alternate Value.
+If
+.Ar parameter
+is unset or null, null is substituted;
+otherwise, the expansion of
+.Ar word
+is substituted.
+.El
+.Pp
+In the parameter expansions shown previously, use of the colon in the
+format results in a test for a parameter that is unset or null; omission
+of the colon results in a test for a parameter that is only unset.
+.Pp
+The
+.Ar word
+inherits the type of quoting
+(unquoted, double-quoted or here-document)
+from the surroundings,
+with the exception that a backslash that quotes a closing brace is removed
+during quote removal.
+.Bl -tag -width indent
+.It Li ${# Ns Ar parameter Ns Li }
+String Length.
+The length in characters of
+the value of
+.Ar parameter .
+.El
+.Pp
+The following four varieties of parameter expansion provide for substring
+processing.
+In each case, pattern matching notation
+(see
+.Sx Shell Patterns ) ,
+rather than regular expression notation,
+is used to evaluate the patterns.
+If parameter is one of the special parameters
+.Va *
+or
+.Va @ ,
+the result of the expansion is unspecified.
+Enclosing the full parameter expansion string in double-quotes does not
+cause the following four varieties of pattern characters to be quoted,
+whereas quoting characters within the braces has this effect.
+.Bl -tag -width indent
+.It Li ${ Ns Ar parameter Ns Li % Ns Ar word Ns Li }
+Remove Smallest Suffix Pattern.
+The
+.Ar word
+is expanded to produce a pattern.
+The
+parameter expansion then results in
+.Ar parameter ,
+with the smallest portion of the
+suffix matched by the pattern deleted.
+.It Li ${ Ns Ar parameter Ns Li %% Ns Ar word Ns Li }
+Remove Largest Suffix Pattern.
+The
+.Ar word
+is expanded to produce a pattern.
+The
+parameter expansion then results in
+.Ar parameter ,
+with the largest portion of the
+suffix matched by the pattern deleted.
+.It Li ${ Ns Ar parameter Ns Li # Ns Ar word Ns Li }
+Remove Smallest Prefix Pattern.
+The
+.Ar word
+is expanded to produce a pattern.
+The
+parameter expansion then results in
+.Ar parameter ,
+with the smallest portion of the
+prefix matched by the pattern deleted.
+.It Li ${ Ns Ar parameter Ns Li ## Ns Ar word Ns Li }
+Remove Largest Prefix Pattern.
+The
+.Ar word
+is expanded to produce a pattern.
+The
+parameter expansion then results in
+.Ar parameter ,
+with the largest portion of the
+prefix matched by the pattern deleted.
+.El
+.Ss Command Substitution
+Command substitution allows the output of a command to be substituted in
+place of the command name itself.
+Command substitution occurs when
+the command is enclosed as follows:
+.Pp
+.D1 Li $( Ns Ar command Ns Li )\&
+.Pp
+or the backquoted version:
+.Pp
+.D1 Li ` Ns Ar command Ns Li `
+.Pp
+The shell expands the command substitution by executing command
+and replacing the command substitution
+with the standard output of the command,
+removing sequences of one or more newlines at the end of the substitution.
+Embedded newlines before the end of the output are not removed;
+however, during field splitting, they may be translated into spaces
+depending on the value of
+.Va IFS
+and the quoting that is in effect.
+The command is executed in a subshell environment,
+except that the built-in commands
+.Ic jobid ,
+.Ic jobs ,
+and
+.Ic trap
+return information about the parent shell environment
+and
+.Ic times
+returns information about the same process
+if they are the only command in a command substitution.
+.Pp
+If a command substitution of the
+.Li $(
+form begins with a subshell,
+the
+.Li $(
+and
+.Li (\&
+must be separated by whitespace
+to avoid ambiguity with arithmetic expansion.
+.Ss Arithmetic Expansion
+Arithmetic expansion provides a mechanism for evaluating an arithmetic
+expression and substituting its value.
+The format for arithmetic expansion is as follows:
+.Pp
+.D1 Li $(( Ns Ar expression Ns Li ))
+.Pp
+The
+.Ar expression
+is treated as if it were in double-quotes, except
+that a double-quote inside the expression is not treated specially.
+The
+shell expands all tokens in the
+.Ar expression
+for parameter expansion,
+command substitution,
+arithmetic expansion
+and quote removal.
+.Pp
+The allowed expressions are a subset of C expressions,
+summarized below.
+.Bl -tag -width "Variables" -offset indent
+.It Values
+All values are of type
+.Ft intmax_t .
+.It Constants
+Decimal, octal (starting with
+.Li 0 )
+and hexadecimal (starting with
+.Li 0x )
+integer constants.
+.It Variables
+Shell variables can be read and written
+and contain integer constants.
+.It Unary operators
+.Li "! ~ + -"
+.It Binary operators
+.Li "* / % + - << >> < <= > >= == != & ^ | && ||"\&
+.It Assignment operators
+.Li "= += -= *= /= %= <<= >>= &= ^= |="
+.It Conditional operator
+.Li "? :"\&
+.El
+.Pp
+The result of the expression is substituted in decimal.
+.Ss White Space Splitting (Field Splitting)
+In certain contexts,
+after parameter expansion, command substitution, and
+arithmetic expansion the shell scans the results of
+expansions and substitutions that did not occur in double-quotes for
+field splitting and multiple fields can result.
+.Pp
+Characters in
+.Va IFS
+that are whitespace
+.Po
+.Aq space ,
+.Aq tab ,
+and
+.Aq newline
+.Pc
+are treated differently from other characters in
+.Va IFS .
+.Pp
+Whitespace in
+.Va IFS
+at the beginning or end of a word is discarded.
+.Pp
+Subsequently, a field is delimited by either
+.Bl -enum
+.It
+a non-whitespace character in
+.Va IFS
+with any whitespace in
+.Va IFS
+surrounding it, or
+.It
+one or more whitespace characters in
+.Va IFS .
+.El
+.Pp
+If a word ends with a non-whitespace character in
+.Va IFS ,
+there is no empty field after this character.
+.Pp
+If no field is delimited, the word is discarded.
+In particular, if a word consists solely of an unquoted substitution
+and the result of the substitution is null,
+it is removed by field splitting even if
+.Va IFS
+is null.
+.Ss Pathname Expansion (File Name Generation)
+Unless the
+.Fl f
+option is set,
+file name generation is performed
+after word splitting is complete.
+Each word is
+viewed as a series of patterns, separated by slashes.
+The
+process of expansion replaces the word with the names of
+all existing files whose names can be formed by replacing
+each pattern with a string that matches the specified pattern.
+There are two restrictions on this: first, a pattern cannot match
+a string containing a slash, and second,
+a pattern cannot match a string starting with a period
+unless the first character of the pattern is a period.
+The next section describes the patterns used for
+Pathname Expansion,
+the four varieties of parameter expansion for substring processing and the
+.Ic case
+command.
+.Ss Shell Patterns
+A pattern consists of normal characters, which match themselves,
+and meta-characters.
+The meta-characters are
+.Ql * ,
+.Ql \&? ,
+and
+.Ql \&[ .
+These characters lose their special meanings if they are quoted.
+When command or variable substitution is performed and the dollar sign
+or back quotes are not double-quoted, the value of the
+variable or the output of the command is scanned for these
+characters and they are turned into meta-characters.
+.Pp
+An asterisk
+.Pq Ql *
+matches any string of characters.
+A question mark
+.Pq Ql \&?
+matches any single character.
+A left bracket
+.Pq Ql \&[
+introduces a character class.
+The end of the character class is indicated by a
+.Ql \&] ;
+if the
+.Ql \&]
+is missing then the
+.Ql \&[
+matches a
+.Ql \&[
+rather than introducing a character class.
+A character class matches any of the characters between the square brackets.
+A locale-dependent range of characters may be specified using a minus sign.
+A named class of characters (see
+.Xr wctype 3 )
+may be specified by surrounding the name with
+.Ql \&[:\&
+and
+.Ql :\&] .
+For example,
+.Ql \&[\&[:alpha:\&]\&]
+is a shell pattern that matches a single letter.
+The character class may be complemented by making an exclamation point
+.Pq Ql !\&
+the first character of the character class.
+A caret
+.Pq Ql ^
+has the same effect but is non-standard.
+.Pp
+To include a
+.Ql \&]
+in a character class, make it the first character listed
+(after the
+.Ql \&!
+or
+.Ql ^ ,
+if any).
+To include a
+.Ql - ,
+make it the first or last character listed.
+.Ss Built-in Commands
+This section lists the built-in commands.
+.Bl -tag -width indent
+.It Ic \&:
+A null command that returns a 0 (true) exit value.
+.It Ic \&. Ar file
+The commands in the specified file are read and executed by the shell.
+The
+.Ic return
+command may be used to return to the
+.Ic \&.
+command's caller.
+If
+.Ar file
+contains any
+.Ql /
+characters, it is used as is.
+Otherwise, the shell searches the
+.Va PATH
+for the file.
+If it is not found in the
+.Va PATH ,
+it is sought in the current working directory.
+.It Ic \&[
+A built-in equivalent of
+.Xr test 1 .
+.It Ic alias Oo Ar name Ns Oo = Ns Ar string Oc ... Oc
+If
+.Ar name Ns = Ns Ar string
+is specified, the shell defines the alias
+.Ar name
+with value
+.Ar string .
+If just
+.Ar name
+is specified, the value of the alias
+.Ar name
+is printed.
+With no arguments, the
+.Ic alias
+built-in command prints the names and values of all defined aliases
+(see
+.Ic unalias ) .
+Alias values are written with appropriate quoting so that they are
+suitable for re-input to the shell.
+Also see the
+.Sx Aliases
+subsection.
+.It Ic bg Op Ar job ...
+Continue the specified jobs
+(or the current job if no jobs are given)
+in the background.
+.It Ic bind Oo Fl aeklrsv Oc Oo Ar key Oo Ar command Oc Oc
+List or alter key bindings for the line editor.
+This command is documented in
+.Xr editrc 5 .
+.It Ic break Op Ar num
+See the
+.Sx Flow-Control Constructs
+subsection.
+.It Ic builtin Ar cmd Op Ar arg ...
+Execute the specified built-in command,
+.Ar cmd .
+This is useful when the user wishes to override a shell function
+with the same name as a built-in command.
+.It Ic cd Oo Fl L | P Oc Oo Fl e Oc Op Ar directory
+.It Ic cd Fl
+Switch to the specified
+.Ar directory ,
+to the directory specified in the
+.Va HOME
+environment variable if no
+.Ar directory
+is specified or
+to the directory specified in the
+.Va OLDPWD
+environment variable if
+.Ar directory
+is
+.Fl .
+If
+.Ar directory
+does not begin with
+.Pa / , \&. ,
+or
+.Pa .. ,
+then the directories listed in the
+.Va CDPATH
+variable will be
+searched for the specified
+.Ar directory .
+If
+.Va CDPATH
+is unset, the current directory is searched.
+The format of
+.Va CDPATH
+is the same as that of
+.Va PATH .
+In an interactive shell,
+the
+.Ic cd
+command will print out the name of the directory
+that it actually switched to
+if the
+.Va CDPATH
+mechanism was used or if
+.Ar directory
+was
+.Fl .
+.Pp
+If the
+.Fl P
+option is specified,
+.Pa ..
+is handled physically and symbolic links are resolved before
+.Pa ..
+components are processed.
+If the
+.Fl L
+option is specified,
+.Pa ..
+is handled logically.
+This is the default.
+.Pp
+The
+.Fl e
+option causes
+.Ic cd
+to return exit status 1 if the full pathname of the new directory
+cannot be determined reliably or at all.
+Normally this is not considered an error,
+although a warning is printed.
+.Pp
+If changing the directory fails, the exit status is greater than 1.
+If the directory is changed, the exit status is 0, or also 1 if
+.Fl e
+was given.
+.It Ic chdir
+A synonym for the
+.Ic cd
+built-in command.
+.It Ic command Oo Fl p Oc Op Ar utility Op Ar argument ...
+.It Ic command Oo Fl p Oc Fl v Ar utility
+.It Ic command Oo Fl p Oc Fl V Ar utility
+The first form of invocation executes the specified
+.Ar utility ,
+ignoring shell functions in the search.
+If
+.Ar utility
+is a special builtin,
+it is executed as if it were a regular builtin.
+.Pp
+If the
+.Fl p
+option is specified, the command search is performed using a
+default value of
+.Va PATH
+that is guaranteed to find all of the standard utilities.
+.Pp
+If the
+.Fl v
+option is specified,
+.Ar utility
+is not executed but a description of its interpretation by the shell is
+printed.
+For ordinary commands the output is the path name; for shell built-in
+commands, shell functions and keywords only the name is written.
+Aliases are printed as
+.Dq Ic alias Ar name Ns = Ns Ar value .
+.Pp
+The
+.Fl V
+option is identical to
+.Fl v
+except for the output.
+It prints
+.Dq Ar utility Ic is Ar description
+where
+.Ar description
+is either
+the path name to
+.Ar utility ,
+a special shell builtin,
+a shell builtin,
+a shell function,
+a shell keyword
+or
+an alias for
+.Ar value .
+.It Ic continue Op Ar num
+See the
+.Sx Flow-Control Constructs
+subsection.
+.It Ic echo Oo Fl e | n Oc Op Ar string ...
+Print a space-separated list of the arguments to the standard output
+and append a newline character.
+.Bl -tag -width indent
+.It Fl n
+Suppress the output of the trailing newline.
+.It Fl e
+Process C-style backslash escape sequences.
+The
+.Ic echo
+command understands the following character escapes:
+.Bl -tag -width indent
+.It \ea
+Alert (ring the terminal bell)
+.It \eb
+Backspace
+.It \ec
+Suppress the trailing newline (this has the side-effect of truncating the
+line if it is not the last character)
+.It \ee
+The ESC character (ASCII 0x1b)
+.It \ef
+Formfeed
+.It \en
+Newline
+.It \er
+Carriage return
+.It \et
+Horizontal tab
+.It \ev
+Vertical tab
+.It \e\e
+Literal backslash
+.It \e0nnn
+(Zero) The character whose octal value is
+.Ar nnn
+.El
+.Pp
+If
+.Ar string
+is not enclosed in quotes then the backslash itself must be escaped
+with a backslash to protect it from the shell.
+For example
+.Bd -literal -offset indent
+$ echo -e "a\evb"
+a
+ b
+$ echo -e a\e\evb
+a
+ b
+$ echo -e "a\e\eb"
+a\eb
+$ echo -e a\e\e\e\eb
+a\eb
+.Ed
+.El
+.Pp
+Only one of the
+.Fl e
+and
+.Fl n
+options may be specified.
+.It Ic eval Ar string ...
+Concatenate all the arguments with spaces.
+Then re-parse and execute the command.
+.It Ic exec Op Ar command Op arg ...
+Unless
+.Ar command
+is omitted,
+the shell process is replaced with the specified program
+(which must be a real program, not a shell built-in command or function).
+Any redirections on the
+.Ic exec
+command are marked as permanent,
+so that they are not undone when the
+.Ic exec
+command finishes.
+.It Ic exit Op Ar exitstatus
+Terminate the shell process.
+If
+.Ar exitstatus
+is given
+it is used as the exit status of the shell.
+Otherwise, if the shell is executing an
+.Cm EXIT
+trap, the exit status of the last command before the trap is used;
+if the shell is executing a trap for a signal,
+the shell exits by resending the signal to itself.
+Otherwise, the exit status of the preceding command is used.
+The exit status should be an integer between 0 and 255.
+.It Ic export Ar name ...
+.It Ic export Op Fl p
+The specified names are exported so that they will
+appear in the environment of subsequent commands.
+The only way to un-export a variable is to
+.Ic unset
+it.
+The shell allows the value of a variable to be set
+at the same time as it is exported by writing
+.Pp
+.D1 Ic export Ar name Ns = Ns Ar value
+.Pp
+With no arguments the
+.Ic export
+command lists the names
+of all exported variables.
+If the
+.Fl p
+option is specified, the exported variables are printed as
+.Dq Ic export Ar name Ns = Ns Ar value
+lines, suitable for re-input to the shell.
+.It Ic false
+A null command that returns a non-zero (false) exit value.
+.It Ic fc Oo Fl e Ar editor Oc Op Ar first Op Ar last
+.It Ic fc Fl l Oo Fl nr Oc Op Ar first Op Ar last
+.It Ic fc Fl s Oo Ar old Ns = Ns Ar new Oc Op Ar first
+The
+.Ic fc
+built-in command lists, or edits and re-executes,
+commands previously entered to an interactive shell.
+.Bl -tag -width indent
+.It Fl e Ar editor
+Use the editor named by
+.Ar editor
+to edit the commands.
+The
+.Ar editor
+string is a command name,
+subject to search via the
+.Va PATH
+variable.
+The value in the
+.Va FCEDIT
+variable is used as a default when
+.Fl e
+is not specified.
+If
+.Va FCEDIT
+is null or unset, the value of the
+.Va EDITOR
+variable is used.
+If
+.Va EDITOR
+is null or unset,
+.Xr ed 1
+is used as the editor.
+.It Fl l No (ell)
+List the commands rather than invoking
+an editor on them.
+The commands are written in the
+sequence indicated by the
+.Ar first
+and
+.Ar last
+operands, as affected by
+.Fl r ,
+with each command preceded by the command number.
+.It Fl n
+Suppress command numbers when listing with
+.Fl l .
+.It Fl r
+Reverse the order of the commands listed
+(with
+.Fl l )
+or edited
+(with neither
+.Fl l
+nor
+.Fl s ) .
+.It Fl s
+Re-execute the command without invoking an editor.
+.It Ar first
+.It Ar last
+Select the commands to list or edit.
+The number of previous commands that can be accessed
+are determined by the value of the
+.Va HISTSIZE
+variable.
+The value of
+.Ar first
+or
+.Ar last
+or both are one of the following:
+.Bl -tag -width indent
+.It Oo Cm + Oc Ns Ar num
+A positive number representing a command number;
+command numbers can be displayed with the
+.Fl l
+option.
+.It Fl Ar num
+A negative decimal number representing the
+command that was executed
+.Ar num
+of
+commands previously.
+For example, \-1 is the immediately previous command.
+.It Ar string
+A string indicating the most recently entered command
+that begins with that string.
+If the
+.Ar old Ns = Ns Ar new
+operand is not also specified with
+.Fl s ,
+the string form of the first operand cannot contain an embedded equal sign.
+.El
+.El
+.Pp
+The following variables affect the execution of
+.Ic fc :
+.Bl -tag -width ".Va HISTSIZE"
+.It Va FCEDIT
+Name of the editor to use for history editing.
+.It Va HISTSIZE
+The number of previous commands that are accessible.
+.El
+.It Ic fg Op Ar job
+Move the specified
+.Ar job
+or the current job to the foreground.
+.It Ic getopts Ar optstring var
+The POSIX
+.Ic getopts
+command.
+The
+.Ic getopts
+command deprecates the older
+.Xr getopt 1
+command.
+The first argument should be a series of letters, each possibly
+followed by a colon which indicates that the option takes an argument.
+The specified variable is set to the parsed option.
+The index of
+the next argument is placed into the shell variable
+.Va OPTIND .
+If an option takes an argument, it is placed into the shell variable
+.Va OPTARG .
+If an invalid option is encountered,
+.Ar var
+is set to
+.Ql \&? .
+It returns a false value (1) when it encounters the end of the options.
+A new set of arguments may be parsed by assigning
+.Li OPTIND=1 .
+.It Ic hash Oo Fl rv Oc Op Ar command ...
+The shell maintains a hash table which remembers the locations of commands.
+With no arguments whatsoever, the
+.Ic hash
+command prints out the contents of this table.
+.Pp
+With arguments, the
+.Ic hash
+command removes each specified
+.Ar command
+from the hash table (unless they are functions) and then locates it.
+With the
+.Fl v
+option,
+.Ic hash
+prints the locations of the commands as it finds them.
+The
+.Fl r
+option causes the
+.Ic hash
+command to delete all the entries in the hash table except for functions.
+.It Ic jobid Op Ar job
+Print the process IDs of the processes in the specified
+.Ar job .
+If the
+.Ar job
+argument is omitted, use the current job.
+.It Ic jobs Oo Fl lps Oc Op Ar job ...
+Print information about the specified jobs, or all jobs if no
+.Ar job
+argument is given.
+The information printed includes job ID, status and command name.
+.Pp
+If the
+.Fl l
+option is specified, the PID of each job is also printed.
+If the
+.Fl p
+option is specified, only the process IDs for the process group leaders
+are printed, one per line.
+If the
+.Fl s
+option is specified, only the PIDs of the job commands are printed, one per
+line.
+.It Ic kill
+A built-in equivalent of
+.Xr kill 1
+that additionally supports sending signals to jobs.
+.It Ic local Oo Ar variable ... Oc Op Fl
+See the
+.Sx Functions
+subsection.
+.It Ic printf
+A built-in equivalent of
+.Xr printf 1 .
+.It Ic pwd Op Fl L | P
+Print the path of the current directory.
+The built-in command may
+differ from the program of the same name because the
+built-in command remembers what the current directory
+is rather than recomputing it each time.
+This makes
+it faster.
+However, if the current directory is
+renamed,
+the built-in version of
+.Xr pwd 1
+will continue to print the old name for the directory.
+.Pp
+If the
+.Fl P
+option is specified, symbolic links are resolved.
+If the
+.Fl L
+option is specified, the shell's notion of the current directory
+is printed (symbolic links are not resolved).
+This is the default.
+.It Ic read Oo Fl p Ar prompt Oc Oo
+.Fl t Ar timeout Oc Oo Fl er Oc Ar variable ...
+The
+.Ar prompt
+is printed if the
+.Fl p
+option is specified
+and the standard input is a terminal.
+Then a line is
+read from the standard input.
+The trailing newline
+is deleted from the line and the line is split as
+described in the section on
+.Sx White Space Splitting (Field Splitting)\&
+above, and
+the pieces are assigned to the variables in order.
+If there are more pieces than variables, the remaining
+pieces (along with the characters in
+.Va IFS
+that separated them)
+are assigned to the last variable.
+If there are more variables than pieces, the remaining
+variables are assigned the null string.
+.Pp
+Backslashes are treated specially, unless the
+.Fl r
+option is
+specified.
+If a backslash is followed by
+a newline, the backslash and the newline will be
+deleted.
+If a backslash is followed by any other
+character, the backslash will be deleted and the following
+character will be treated as though it were not in
+.Va IFS ,
+even if it is.
+.Pp
+If the
+.Fl t
+option is specified and the
+.Ar timeout
+elapses before a complete line of input is supplied,
+the
+.Ic read
+command will return an exit status as if terminated by
+.Dv SIGALRM
+without assigning any values.
+The
+.Ar timeout
+value may optionally be followed by one of
+.Ql s ,
+.Ql m
+or
+.Ql h
+to explicitly specify seconds, minutes or hours.
+If none is supplied,
+.Ql s
+is assumed.
+.Pp
+The
+.Fl e
+option exists only for backward compatibility with older scripts.
+.Pp
+The exit status is 0 on success, 1 on end of file,
+between 2 and 128 if an error occurs
+and greater than 128 if a trapped signal interrupts
+.Ic read .
+.It Ic readonly Oo Fl p Oc Op Ar name ...
+Each specified
+.Ar name
+is marked as read only,
+so that it cannot be subsequently modified or unset.
+The shell allows the value of a variable to be set
+at the same time as it is marked read only
+by using the following form:
+.Pp
+.D1 Ic readonly Ar name Ns = Ns Ar value
+.Pp
+With no arguments the
+.Ic readonly
+command lists the names of all read only variables.
+If the
+.Fl p
+option is specified, the read-only variables are printed as
+.Dq Ic readonly Ar name Ns = Ns Ar value
+lines, suitable for re-input to the shell.
+.It Ic return Op Ar exitstatus
+See the
+.Sx Functions
+subsection.
+.It Ic set Oo Fl /+abCEefIimnpTuVvx Oc Oo Fl /+o Ar longname Oc Oo
+.Fl c Ar string Oc Op Fl - Ar arg ...
+The
+.Ic set
+command performs three different functions:
+.Bl -item
+.It
+With no arguments, it lists the values of all shell variables.
+.It
+If options are given,
+either in short form or using the long
+.Dq Fl /+o Ar longname
+form,
+it sets or clears the specified options as described in the section called
+.Sx Argument List Processing .
+.It
+If the
+.Dq Fl -
+option is specified,
+.Ic set
+will replace the shell's positional parameters with the subsequent
+arguments.
+If no arguments follow the
+.Dq Fl -
+option,
+all the positional parameters will be cleared,
+which is equivalent to executing the command
+.Dq Li "shift $#" .
+The
+.Dq Fl -
+flag may be omitted when specifying arguments to be used
+as positional replacement parameters.
+This is not recommended,
+because the first argument may begin with a dash
+.Pq Ql -
+or a plus
+.Pq Ql + ,
+which the
+.Ic set
+command will interpret as a request to enable or disable options.
+.El
+.It Ic setvar Ar variable value
+Assigns the specified
+.Ar value
+to the specified
+.Ar variable .
+The
+.Ic setvar
+command is intended to be used in functions that
+assign values to variables whose names are passed as parameters.
+In general it is better to write
+.Dq Ar variable Ns = Ns Ar value
+rather than using
+.Ic setvar .
+.It Ic shift Op Ar n
+Shift the positional parameters
+.Ar n
+times, or once if
+.Ar n
+is not specified.
+A shift sets the value of
+.Li $1
+to the value of
+.Li $2 ,
+the value of
+.Li $2
+to the value of
+.Li $3 ,
+and so on,
+decreasing the value of
+.Li $#
+by one.
+For portability, shifting if there are zero positional parameters
+should be avoided, since the shell may abort.
+.It Ic test
+A built-in equivalent of
+.Xr test 1 .
+.It Ic times
+Print the amount of time spent executing the shell process and its children.
+The first output line shows the user and system times for the shell process
+itself, the second one contains the user and system times for the
+children.
+.It Ic trap Oo Ar action Oc Ar signal ...
+.It Ic trap Fl l
+Cause the shell to parse and execute
+.Ar action
+when any specified
+.Ar signal
+is received.
+The signals are specified by name or number.
+In addition, the pseudo-signal
+.Cm EXIT
+may be used to specify an
+.Ar action
+that is performed when the shell terminates.
+The
+.Ar action
+may be an empty string or a dash
+.Pq Ql - ;
+the former causes the specified signal to be ignored
+and the latter causes the default action to be taken.
+Omitting the
+.Ar action
+and using only signal numbers is another way to request the default action.
+In a subshell or utility environment,
+the shell resets trapped (but not ignored) signals to the default action.
+The
+.Ic trap
+command has no effect on signals that were ignored on entry to the shell.
+.Pp
+Option
+.Fl l
+causes the
+.Ic trap
+command to display a list of valid signal names.
+.It Ic true
+A null command that returns a 0 (true) exit value.
+.It Ic type Op Ar name ...
+Interpret each
+.Ar name
+as a command and print the resolution of the command search.
+Possible resolutions are:
+shell keyword, alias, special shell builtin, shell builtin, command,
+tracked alias
+and not found.
+For aliases the alias expansion is printed;
+for commands and tracked aliases
+the complete pathname of the command is printed.
+.It Ic ulimit Oo Fl HSabcdfklmnopstuvw Oc Op Ar limit
+Set or display resource limits (see
+.Xr getrlimit 2 ) .
+If
+.Ar limit
+is specified, the named resource will be set;
+otherwise the current resource value will be displayed.
+.Pp
+If
+.Fl H
+is specified, the hard limits will be set or displayed.
+While everybody is allowed to reduce a hard limit,
+only the superuser can increase it.
+The
+.Fl S
+option
+specifies the soft limits instead.
+When displaying limits,
+only one of
+.Fl S
+or
+.Fl H
+can be given.
+The default is to display the soft limits,
+and to set both the hard and the soft limits.
+.Pp
+Option
+.Fl a
+causes the
+.Ic ulimit
+command to display all resources.
+The parameter
+.Ar limit
+is not acceptable in this mode.
+.Pp
+The remaining options specify which resource value is to be
+displayed or modified.
+They are mutually exclusive.
+.Bl -tag -width indent
+.It Fl b Ar sbsize
+The maximum size of socket buffer usage, in bytes.
+.It Fl c Ar coredumpsize
+The maximal size of core dump files, in 512-byte blocks.
+Setting
+.Ar coredumpsize
+to 0 prevents core dump files from being created.
+.It Fl d Ar datasize
+The maximal size of the data segment of a process, in kilobytes.
+.It Fl f Ar filesize
+The maximal size of a file, in 512-byte blocks.
+.It Fl k Ar kqueues
+The maximal number of kqueues
+(see
+.Xr kqueue 2 )
+for this user ID.
+.It Fl l Ar lockedmem
+The maximal size of memory that can be locked by a process, in
+kilobytes.
+.It Fl m Ar memoryuse
+The maximal resident set size of a process, in kilobytes.
+.It Fl n Ar nofiles
+The maximal number of descriptors that could be opened by a process.
+.It Fl o Ar umtxp
+The maximal number of process-shared locks
+(see
+.Xr pthread 3 )
+for this user ID.
+.It Fl p Ar pseudoterminals
+The maximal number of pseudo-terminals for this user ID.
+.It Fl s Ar stacksize
+The maximal size of the stack segment, in kilobytes.
+.It Fl t Ar time
+The maximal amount of CPU time to be used by each process, in seconds.
+.It Fl u Ar userproc
+The maximal number of simultaneous processes for this user ID.
+.It Fl v Ar virtualmem
+The maximal virtual size of a process, in kilobytes.
+.It Fl w Ar swapuse
+The maximum amount of swap space reserved or used for this user ID,
+in kilobytes.
+.El
+.It Ic umask Oo Fl S Oc Op Ar mask
+Set the file creation mask (see
+.Xr umask 2 )
+to the octal or symbolic (see
+.Xr chmod 1 )
+value specified by
+.Ar mask .
+If the argument is omitted, the current mask value is printed.
+If the
+.Fl S
+option is specified, the output is symbolic, otherwise the output is octal.
+.It Ic unalias Oo Fl a Oc Op Ar name ...
+The specified alias names are removed.
+If
+.Fl a
+is specified, all aliases are removed.
+.It Ic unset Oo Fl fv Oc Ar name ...
+The specified variables or functions are unset and unexported.
+If the
+.Fl v
+option is specified or no options are given, the
+.Ar name
+arguments are treated as variable names.
+If the
+.Fl f
+option is specified, the
+.Ar name
+arguments are treated as function names.
+.It Ic wait Op Ar job ...
+Wait for each specified
+.Ar job
+to complete and return the exit status of the last process in the
+last specified
+.Ar job .
+If any
+.Ar job
+specified is unknown to the shell, it is treated as if it
+were a known job that exited with exit status 127.
+If no operands are given, wait for all jobs to complete
+and return an exit status of zero.
+.El
+.Ss Command Line Editing
+When
+.Nm
+is being used interactively from a terminal, the current command
+and the command history
+(see
+.Ic fc
+in
+.Sx Built-in Commands )
+can be edited using
+.Nm vi Ns -mode
+command line editing.
+This mode uses commands similar
+to a subset of those described in the
+.Xr vi 1
+man page.
+The command
+.Dq Li "set -o vi"
+(or
+.Dq Li "set -V" )
+enables
+.Nm vi Ns -mode
+editing and places
+.Nm
+into
+.Nm vi
+insert mode.
+With
+.Nm vi Ns -mode
+enabled,
+.Nm
+can be switched between insert mode and command mode by typing
+.Aq ESC .
+Hitting
+.Aq return
+while in command mode will pass the line to the shell.
+.Pp
+Similarly, the
+.Dq Li "set -o emacs"
+(or
+.Dq Li "set -E" )
+command can be used to enable a subset of
+.Nm emacs Ns -style
+command line editing features.
+.Sh ENVIRONMENT
+The following environment variables affect the execution of
+.Nm :
+.Bl -tag -width ".Ev LANGXXXXXX"
+.It Ev ENV
+Initialization file for interactive shells.
+.It Ev LANG , Ev LC_*
+Locale settings.
+These are inherited by children of the shell,
+and is used in a limited manner by the shell itself.
+.It Ev OLDPWD
+The previous current directory.
+This is used and updated by
+.Ic cd .
+.It Ev PWD
+An absolute pathname for the current directory,
+possibly containing symbolic links.
+This is used and updated by the shell.
+.It Ev TERM
+The default terminal setting for the shell.
+This is inherited by children of the shell, and is used in the history
+editing modes.
+.El
+.Pp
+Additionally, environment variables are turned into shell variables
+at startup,
+which may affect the shell as described under
+.Sx Special Variables .
+.Sh FILES
+.Bl -tag -width "/etc/suid_profileXX" -compact
+.It Pa ~/.profile
+User's login profile.
+.It Pa /etc/profile
+System login profile.
+.It Pa /etc/shells
+Shell database.
+.It Pa /etc/suid_profile
+Privileged shell profile.
+.El
+.Sh EXIT STATUS
+Errors that are detected by the shell, such as a syntax error, will
+cause the shell to exit with a non-zero exit status.
+If the shell is not an interactive shell, the execution of the shell
+file will be aborted.
+Otherwise the shell will return the exit status of the last command
+executed, or if the
+.Ic exit
+builtin is used with a numeric argument, it
+will return the argument.
+.Sh SEE ALSO
+.Xr 1sh-kill 1 ,
+.Xr 1sh-printf 1 ,
+.Xr 1sh-test 1 ,
+.Xr builtin 1 ,
+.Xr chsh 1 ,
+.Xr echo 1 ,
+.Xr ed 1 ,
+.Xr emacs 1 ,
+.Xr pwd 1 ,
+.Xr vi 1 ,
+.Xr execve 2 ,
+.Xr getrlimit 2 ,
+.Xr umask 2 ,
+.Xr wctype 3 ,
+.Xr editrc 5 ,
+.Xr shells 5
+.Sh HISTORY
+A
+.Nm sh
+command, the Thompson shell, appeared in
+.At v1 .
+It was superseded in
+.At v7
+by the Bourne shell, which inherited the name
+.Nm sh .
+.Pp
+This version of
+.Nm sh
+was rewritten in 1989 under the
+.Bx
+license after the Bourne shell from
+.At V.4 .
+The
+.Nm
+command is based on sources from
+.Fx 12.1 .
+.Sh AUTHORS
+This version of
+.Nm
+was originally written by
+.An Kenneth Almquist .
+.Sh BUGS
+The
+.Nm
+utility does not recognize multibyte characters other than UTF-8.
+Splitting using
+.Va IFS
+does not recognize multibyte characters.
diff --git a/bin/1sh/Makefile b/bin/1sh/Makefile
new file mode 100644
index 00000000..26ce125f
--- /dev/null
+++ b/bin/1sh/Makefile
@@ -0,0 +1,84 @@
+PREFIX = /usr/local
+MANDIR = ${PREFIX}/share/man
+
+CFLAGS += -std=c99 -Wall -Wextra -DSHELL
+LDLIBS = -ledit
+
+-include config.mk
+
+SRCS += alias.c
+SRCS += arith_yacc.c
+SRCS += arith_yylex.c
+SRCS += cd.c
+SRCS += echo.c
+SRCS += error.c
+SRCS += eval.c
+SRCS += exec.c
+SRCS += expand.c
+SRCS += histedit.c
+SRCS += input.c
+SRCS += jobs.c
+SRCS += kill.c
+SRCS += mail.c
+SRCS += main.c
+SRCS += memalloc.c
+SRCS += miscbltin.c
+SRCS += mystring.c
+SRCS += options.c
+SRCS += output.c
+SRCS += parser.c
+SRCS += printf.c
+SRCS += redir.c
+SRCS += show.c
+SRCS += test.c
+SRCS += trap.c
+SRCS += var.c
+
+GENSRCS = builtins.c nodes.c syntax.c
+GENHDRS = builtins.h nodes.h syntax.h token.h
+
+SRCS += ${GENSRCS}
+OBJS = ${SRCS:.c=.o}
+
+MANS = 1sh.1 1sh-kill.1 1sh-printf.1 1sh-test.1
+
+all: tags 1sh
+
+1sh: ${OBJS}
+	${CC} ${LDFLAGS} ${OBJS} ${LDLIBS} -o $@
+
+${OBJS}: ${GENHDRS}
+
+builtins.c builtins.h: mkbuiltins builtins.def
+	sh mkbuiltins .
+
+nodes.c nodes.h: mknodes nodetypes nodes.c.pat
+	./mknodes nodetypes nodes.c.pat
+
+syntax.c syntax.h: mksyntax
+	./mksyntax
+
+token.h: mktokens
+	sh mktokens
+
+tags: *.h *.c
+	ctags -w *.h *.c
+
+depend: ${SRCS} ${GENHDRS}
+	${CC} ${CFLAGS} -MM ${SRCS} > .depend
+
+-include .depend
+
+clean:
+	rm -f 1sh ${OBJS} mknodes mksyntax ${GENSRCS} ${GENHDRS} tags .depend
+
+install: 1sh ${MANS}
+	install -d ${PREFIX}/bin ${MANDIR}/man1
+	install 1sh ${PREFIX}/bin
+	for man in ${MANS}; do gzip -c $$man > ${MANDIR}/man1/$$man.gz; done
+	grep -q '^${PREFIX}/bin/1sh$$' /etc/shells \
+		|| echo '${PREFIX}/bin/1sh' >> /etc/shells
+
+uninstall:
+	rm -f ${PREFIX}/bin/1sh ${MANS:%=${MANDIR}/man1/%.gz}
+	sed -i sed '\;^${PREFIX}/bin/1sh$$;d' /etc/shells
diff --git a/bin/1sh/TOUR b/bin/1sh/TOUR
new file mode 100644
index 00000000..3f196c9b
--- /dev/null
+++ b/bin/1sh/TOUR
@@ -0,0 +1,301 @@
+#	@(#)TOUR	8.1 (Berkeley) 5/31/93
+# $FreeBSD: releng/12.1/bin/sh/TOUR 317882 2017-05-06 13:28:42Z jilles $
+
+NOTE -- This is the original TOUR paper distributed with ash and
+does not represent the current state of the shell.  It is provided anyway
+since it provides helpful information for how the shell is structured,
+but be warned that things have changed -- the current shell is
+still under development.
+
+================================================================
+
+                       A Tour through Ash
+
+               Copyright 1989 by Kenneth Almquist.
+
+
+DIRECTORIES:  The subdirectory bltin contains commands which can
+be compiled stand-alone.  The rest of the source is in the main
+ash directory.
+
+SOURCE CODE GENERATORS:  Files whose names begin with "mk" are
+programs that generate source code.  A complete list of these
+programs is:
+
+        program         input files         generates
+        -------         -----------         ---------
+        mkbuiltins      builtins.def        builtins.h builtins.c
+        mknodes         nodetypes           nodes.h nodes.c
+        mksyntax            -               syntax.h syntax.c
+        mktokens            -               token.h
+
+There are undoubtedly too many of these.
+
+EXCEPTIONS:  Code for dealing with exceptions appears in
+exceptions.c.  The C language doesn't include exception handling,
+so I implement it using setjmp and longjmp.  The global variable
+exception contains the type of exception.  EXERROR is raised by
+calling error.  EXINT is an interrupt.
+
+INTERRUPTS:  In an interactive shell, an interrupt will cause an
+EXINT exception to return to the main command loop.  (Exception:
+EXINT is not raised if the user traps interrupts using the trap
+command.)  The INTOFF and INTON macros (defined in exception.h)
+provide uninterruptible critical sections.  Between the execution
+of INTOFF and the execution of INTON, interrupt signals will be
+held for later delivery.  INTOFF and INTON can be nested.
+
+MEMALLOC.C:  Memalloc.c defines versions of malloc and realloc
+which call error when there is no memory left.  It also defines a
+stack oriented memory allocation scheme.  Allocating off a stack
+is probably more efficient than allocation using malloc, but the
+big advantage is that when an exception occurs all we have to do
+to free up the memory in use at the time of the exception is to
+restore the stack pointer.  The stack is implemented using a
+linked list of blocks.
+
+STPUTC:  If the stack were contiguous, it would be easy to store
+strings on the stack without knowing in advance how long the
+string was going to be:
+        p = stackptr;
+        *p++ = c;       /* repeated as many times as needed */
+        stackptr = p;
+The following three macros (defined in memalloc.h) perform these
+operations, but grow the stack if you run off the end:
+        STARTSTACKSTR(p);
+        STPUTC(c, p);   /* repeated as many times as needed */
+        grabstackstr(p);
+
+We now start a top-down look at the code:
+
+MAIN.C:  The main routine performs some initialization, executes
+the user's profile if necessary, and calls cmdloop.  Cmdloop
+repeatedly parses and executes commands.
+
+OPTIONS.C:  This file contains the option processing code.  It is
+called from main to parse the shell arguments when the shell is
+invoked, and it also contains the set builtin.  The -i and -m op-
+tions (the latter turns on job control) require changes in signal
+handling.  The routines setjobctl (in jobs.c) and setinteractive
+(in trap.c) are called to handle changes to these options.
+
+PARSING:  The parser code is all in parser.c.  A recursive des-
+cent parser is used.  Syntax tables (generated by mksyntax) are
+used to classify characters during lexical analysis.  There are
+four tables:  one for normal use, one for use when inside single
+quotes and dollar single quotes, one for use when inside double
+quotes and one for use in arithmetic.  The tables are machine
+dependent because they are indexed by character variables and
+the range of a char varies from machine to machine.
+
+PARSE OUTPUT:  The output of the parser consists of a tree of
+nodes.  The various types of nodes are defined in the file node-
+types.
+
+Nodes of type NARG are used to represent both words and the con-
+tents of here documents.  An early version of ash kept the con-
+tents of here documents in temporary files, but keeping here do-
+cuments in memory typically results in significantly better per-
+formance.  It would have been nice to make it an option to use
+temporary files for here documents, for the benefit of small
+machines, but the code to keep track of when to delete the tem-
+porary files was complex and I never fixed all the bugs in it.
+(AT&T has been maintaining the Bourne shell for more than ten
+years, and to the best of my knowledge they still haven't gotten
+it to handle temporary files correctly in obscure cases.)
+
+The text field of a NARG structure points to the text of the
+word.  The text consists of ordinary characters and a number of
+special codes defined in parser.h.  The special codes are:
+
+        CTLVAR              Parameter expansion
+        CTLENDVAR           End of parameter expansion
+        CTLBACKQ            Command substitution
+        CTLBACKQ|CTLQUOTE   Command substitution inside double quotes
+        CTLARI              Arithmetic expansion
+        CTLENDARI           End of arithmetic expansion
+        CTLESC              Escape next character
+
+A variable substitution contains the following elements:
+
+        CTLVAR type name '=' [ alternative-text CTLENDVAR ]
+
+The type field is a single character specifying the type of sub-
+stitution.  The possible types are:
+
+        VSNORMAL            $var
+        VSMINUS             ${var-text}
+        VSMINUS|VSNUL       ${var:-text}
+        VSPLUS              ${var+text}
+        VSPLUS|VSNUL        ${var:+text}
+        VSQUESTION          ${var?text}
+        VSQUESTION|VSNUL    ${var:?text}
+        VSASSIGN            ${var=text}
+        VSASSIGN|VSNUL      ${var:=text}
+        VSTRIMLEFT          ${var#text}
+        VSTRIMLEFTMAX       ${var##text}
+        VSTRIMRIGHT         ${var%text}
+        VSTRIMRIGHTMAX      ${var%%text}
+        VSLENGTH            ${#var}
+        VSERROR             delayed error
+
+In addition, the type field will have the VSQUOTE flag set if the
+variable is enclosed in double quotes and the VSLINENO flag if
+LINENO is being expanded (the parameter name is the decimal line
+number).  The parameter's name comes next, terminated by an equals
+sign.  If the type is not VSNORMAL (including when it is VSLENGTH),
+then the text field in the substitution follows, terminated by a
+CTLENDVAR byte.
+
+The type VSERROR is used to allow parsing bad substitutions like
+${var[7]} and generate an error when they are expanded.
+
+Commands in back quotes are parsed and stored in a linked list.
+The locations of these commands in the string are indicated by
+CTLBACKQ and CTLBACKQ+CTLQUOTE characters, depending upon whether
+the back quotes were enclosed in double quotes.
+
+Arithmetic expansion starts with CTLARI and ends with CTLENDARI.
+
+The character CTLESC escapes the next character, so that in case
+any of the CTL characters mentioned above appear in the input,
+they can be passed through transparently.  CTLESC is also used to
+escape '*', '?', '[', and '!' characters which were quoted by the
+user and thus should not be used for file name generation.
+
+CTLESC characters have proved to be particularly tricky to get
+right.  In the case of here documents which are not subject to
+variable and command substitution, the parser doesn't insert any
+CTLESC characters to begin with (so the contents of the text
+field can be written without any processing).  Other here docu-
+ments, and words which are not subject to file name generation,
+have the CTLESC characters removed during the variable and command
+substitution phase.  Words which are subject to file name
+generation have the CTLESC characters removed as part of the file
+name phase.
+
+EXECUTION:  Command execution is handled by the following files:
+        eval.c     The top level routines.
+        redir.c    Code to handle redirection of input and output.
+        jobs.c     Code to handle forking, waiting, and job control.
+        exec.c     Code to do path searches and the actual exec sys call.
+        expand.c   Code to evaluate arguments.
+        var.c      Maintains the variable symbol table.  Called from expand.c.
+
+EVAL.C:  Evaltree recursively executes a parse tree.  The exit
+status is returned in the global variable exitstatus.  The alter-
+native entry evalbackcmd is called to evaluate commands in back
+quotes.  It saves the result in memory if the command is a buil-
+tin; otherwise it forks off a child to execute the command and
+connects the standard output of the child to a pipe.
+
+JOBS.C:  To create a process, you call makejob to return a job
+structure, and then call forkshell (passing the job structure as
+an argument) to create the process.  Waitforjob waits for a job
+to complete.  These routines take care of process groups if job
+control is defined.
+
+REDIR.C:  Ash allows file descriptors to be redirected and then
+restored without forking off a child process.  This is accom-
+plished by duplicating the original file descriptors.  The redir-
+tab structure records where the file descriptors have been dupli-
+cated to.
+
+EXEC.C:  The routine find_command locates a command, and enters
+the command in the hash table if it is not already there.  The
+third argument specifies whether it is to print an error message
+if the command is not found.  (When a pipeline is set up,
+find_command is called for all the commands in the pipeline be-
+fore any forking is done, so to get the commands into the hash
+table of the parent process.  But to make command hashing as
+transparent as possible, we silently ignore errors at that point
+and only print error messages if the command cannot be found
+later.)
+
+The routine shellexec is the interface to the exec system call.
+
+EXPAND.C:  As the routine argstr generates words by parameter
+expansion, command substitution and arithmetic expansion, it
+performs word splitting on the result.  As each word is output,
+the routine expandmeta performs file name generation (if enabled).
+
+VAR.C:  Variables are stored in a hash table.  Probably we should
+switch to extensible hashing.  The variable name is stored in the
+same string as the value (using the format "name=value") so that
+no string copying is needed to create the environment of a com-
+mand.  Variables which the shell references internally are preal-
+located so that the shell can reference the values of these vari-
+ables without doing a lookup.
+
+When a program is run, the code in eval.c sticks any environment
+variables which precede the command (as in "PATH=xxx command") in
+the variable table as the simplest way to strip duplicates, and
+then calls "environment" to get the value of the environment.
+
+BUILTIN COMMANDS:  The procedures for handling these are scat-
+tered throughout the code, depending on which location appears
+most appropriate.  They can be recognized because their names al-
+ways end in "cmd".  The mapping from names to procedures is
+specified in the file builtins.def, which is processed by the
+mkbuiltins command.
+
+A builtin command is invoked with argc and argv set up like a
+normal program.  A builtin command is allowed to overwrite its
+arguments.  Builtin routines can call nextopt to do option pars-
+ing.  This is kind of like getopt, but you don't pass argc and
+argv to it.  Builtin routines can also call error.  This routine
+normally terminates the shell (or returns to the main command
+loop if the shell is interactive), but when called from a non-
+special builtin command it causes the builtin command to
+terminate with an exit status of 2.
+
+The directory bltins contains commands which can be compiled in-
+dependently but can also be built into the shell for efficiency
+reasons.  The header file bltin.h takes care of most of the
+differences between the ash and the stand-alone environment.
+The user should call the main routine "main", and #define main to
+be the name of the routine to use when the program is linked into
+ash.  This #define should appear before bltin.h is included;
+bltin.h will #undef main if the program is to be compiled
+stand-alone. A similar approach is used for a few utilities from
+bin and usr.bin.
+
+CD.C:  This file defines the cd and pwd builtins.
+
+SIGNALS:  Trap.c implements the trap command.  The routine set-
+signal figures out what action should be taken when a signal is
+received and invokes the signal system call to set the signal ac-
+tion appropriately.  When a signal that a user has set a trap for
+is caught, the routine "onsig" sets a flag.  The routine dotrap
+is called at appropriate points to actually handle the signal.
+When an interrupt is caught and no trap has been set for that
+signal, the routine "onint" in error.c is called.
+
+OUTPUT:  Ash uses its own output routines.  There are three out-
+put structures allocated.  "Output" represents the standard out-
+put, "errout" the standard error, and "memout" contains output
+which is to be stored in memory.  This last is used when a buil-
+tin command appears in backquotes, to allow its output to be col-
+lected without doing any I/O through the UNIX operating system.
+The variables out1 and out2 normally point to output and errout,
+respectively, but they are set to point to memout when appropri-
+ate inside backquotes.
+
+INPUT:  The basic input routine is pgetc, which reads from the
+current input file.  There is a stack of input files; the current
+input file is the top file on this stack.  The code allows the
+input to come from a string rather than a file.  (This is for the
+-c option and the "." and eval builtin commands.)  The global
+variable plinno is saved and restored when files are pushed and
+popped from the stack.  The parser routines store the number of
+the current line in this variable.
+
+DEBUGGING:  If DEBUG is defined in shell.h, then the shell will
+write debugging information to the file $HOME/trace.  Most of
+this is done using the TRACE macro, which takes a set of printf
+arguments inside two sets of parenthesis.  Example:
+"TRACE(("n=%d0, n))".  The double parenthesis are necessary be-
+cause the preprocessor can't handle functions with a variable
+number of arguments.  Defining DEBUG also causes the shell to
+generate a core dump if it is sent a quit signal.  The tracing
+code is in show.c.
diff --git a/bin/1sh/alias.c b/bin/1sh/alias.c
new file mode 100644
index 00000000..e343b853
--- /dev/null
+++ b/bin/1sh/alias.c
@@ -0,0 +1,256 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)alias.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/alias.c 317039 2017-04-16 22:10:02Z jilles $ */
+
+#include <stdlib.h>
+#include "shell.h"
+#include "output.h"
+#include "error.h"
+#include "memalloc.h"
+#include "mystring.h"
+#include "alias.h"
+#include "options.h"
+#include "builtins.h"
+
+#define ATABSIZE 39
+
+static struct alias *atab[ATABSIZE];
+static int aliases;
+
+static void setalias(const char *, const char *);
+static int unalias(const char *);
+static struct alias **hashalias(const char *);
+
+static
+void
+setalias(const char *name, const char *val)
+{
+	struct alias *ap, **app;
+
+	unalias(name);
+	app = hashalias(name);
+	INTOFF;
+	ap = ckmalloc(sizeof (struct alias));
+	ap->name = savestr(name);
+	ap->val = savestr(val);
+	ap->flag = 0;
+	ap->next = *app;
+	*app = ap;
+	aliases++;
+	INTON;
+}
+
+static void
+freealias(struct alias *ap)
+{
+	ckfree(ap->name);
+	ckfree(ap->val);
+	ckfree(ap);
+}
+
+static int
+unalias(const char *name)
+{
+	struct alias *ap, **app;
+
+	app = hashalias(name);
+
+	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
+		if (equal(name, ap->name)) {
+			/*
+			 * if the alias is currently in use (i.e. its
+			 * buffer is being used by the input routine) we
+			 * just null out the name instead of freeing it.
+			 * We could clear it out later, but this situation
+			 * is so rare that it hardly seems worth it.
+			 */
+			if (ap->flag & ALIASINUSE)
+				*ap->name = '\0';
+			else {
+				INTOFF;
+				*app = ap->next;
+				freealias(ap);
+				INTON;
+			}
+			aliases--;
+			return (0);
+		}
+	}
+
+	return (1);
+}
+
+static void
+rmaliases(void)
+{
+	struct alias *ap, **app;
+	int i;
+
+	INTOFF;
+	for (i = 0; i < ATABSIZE; i++) {
+		app = &atab[i];
+		while (*app) {
+			ap = *app;
+			if (ap->flag & ALIASINUSE) {
+				*ap->name = '\0';
+				app = &(*app)->next;
+			} else {
+				*app = ap->next;
+				freealias(ap);
+			}
+		}
+	}
+	aliases = 0;
+	INTON;
+}
+
+struct alias *
+lookupalias(const char *name, int check)
+{
+	struct alias *ap;
+
+	if (aliases == 0)
+		return (NULL);
+	for (ap = *hashalias(name); ap; ap = ap->next) {
+		if (equal(name, ap->name)) {
+			if (check && (ap->flag & ALIASINUSE))
+				return (NULL);
+			return (ap);
+		}
+	}
+
+	return (NULL);
+}
+
+static int
+comparealiases(const void *p1, const void *p2)
+{
+	const struct alias *const *a1 = p1;
+	const struct alias *const *a2 = p2;
+
+	return strcmp((*a1)->name, (*a2)->name);
+}
+
+static void
+printalias(const struct alias *a)
+{
+	out1fmt("%s=", a->name);
+	out1qstr(a->val);
+	out1c('\n');
+}
+
+static void
+printaliases(void)
+{
+	int i, j;
+	struct alias **sorted, *ap;
+
+	INTOFF;
+	sorted = ckmalloc(aliases * sizeof(*sorted));
+	j = 0;
+	for (i = 0; i < ATABSIZE; i++)
+		for (ap = atab[i]; ap; ap = ap->next)
+			if (*ap->name != '\0')
+				sorted[j++] = ap;
+	qsort(sorted, aliases, sizeof(*sorted), comparealiases);
+	for (i = 0; i < aliases; i++) {
+		printalias(sorted[i]);
+		if (int_pending())
+			break;
+	}
+	ckfree(sorted);
+	INTON;
+}
+
+int
+aliascmd(int argc __unused, char **argv __unused)
+{
+	char *n, *v;
+	int ret = 0;
+	struct alias *ap;
+
+	nextopt("");
+
+	if (*argptr == NULL) {
+		printaliases();
+		return (0);
+	}
+	while ((n = *argptr++) != NULL) {
+		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
+			if ((ap = lookupalias(n, 0)) == NULL) {
+				warning("%s: not found", n);
+				ret = 1;
+			} else
+				printalias(ap);
+		else {
+			*v++ = '\0';
+			setalias(n, v);
+		}
+	}
+
+	return (ret);
+}
+
+int
+unaliascmd(int argc __unused, char **argv __unused)
+{
+	int i;
+
+	while ((i = nextopt("a")) != '\0') {
+		if (i == 'a') {
+			rmaliases();
+			return (0);
+		}
+	}
+	for (i = 0; *argptr; argptr++)
+		i |= unalias(*argptr);
+
+	return (i);
+}
+
+static struct alias **
+hashalias(const char *p)
+{
+	unsigned int hashval;
+
+	hashval = (unsigned char)*p << 4;
+	while (*p)
+		hashval+= *p++;
+	return &atab[hashval % ATABSIZE];
+}
diff --git a/bin/1sh/alias.h b/bin/1sh/alias.h
new file mode 100644
index 00000000..625d1a50
--- /dev/null
+++ b/bin/1sh/alias.h
@@ -0,0 +1,45 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)alias.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/alias.h 314436 2017-02-28 23:42:47Z imp $
+ */
+
+#define ALIASINUSE	1
+
+struct alias {
+	struct alias *next;
+	char *name;
+	char *val;
+	int flag;
+};
+
+struct alias *lookupalias(const char *, int);
diff --git a/bin/1sh/arith.h b/bin/1sh/arith.h
new file mode 100644
index 00000000..ecaad30f
--- /dev/null
+++ b/bin/1sh/arith.h
@@ -0,0 +1,37 @@
+/*-
+ * Copyright (c) 1995
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)arith.h	1.1 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/arith.h 315511 2017-03-18 20:41:07Z jilles $
+ */
+
+#include "shell.h"
+
+#define DIGITS(var) (3 + (2 + CHAR_BIT * sizeof((var))) / 3)
+
+arith_t arith(const char *);
diff --git a/bin/1sh/arith_yacc.c b/bin/1sh/arith_yacc.c
new file mode 100644
index 00000000..57285831
--- /dev/null
+++ b/bin/1sh/arith_yacc.c
@@ -0,0 +1,381 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2007
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/arith_yacc.c 345117 2019-03-13 21:53:10Z jilles $ */
+
+#include <limits.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "arith.h"
+#include "arith_yacc.h"
+#include "expand.h"
+#include "shell.h"
+#include "error.h"
+#include "memalloc.h"
+#include "output.h"
+#include "options.h"
+#include "var.h"
+
+#if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ
+#error Arithmetic tokens are out of order.
+#endif
+
+static const char *arith_startbuf;
+
+const char *arith_buf;
+union yystype yylval;
+
+static int last_token;
+
+#define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec
+
+static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = {
+	ARITH_PRECEDENCE(ARITH_MUL, 0),
+	ARITH_PRECEDENCE(ARITH_DIV, 0),
+	ARITH_PRECEDENCE(ARITH_REM, 0),
+	ARITH_PRECEDENCE(ARITH_ADD, 1),
+	ARITH_PRECEDENCE(ARITH_SUB, 1),
+	ARITH_PRECEDENCE(ARITH_LSHIFT, 2),
+	ARITH_PRECEDENCE(ARITH_RSHIFT, 2),
+	ARITH_PRECEDENCE(ARITH_LT, 3),
+	ARITH_PRECEDENCE(ARITH_LE, 3),
+	ARITH_PRECEDENCE(ARITH_GT, 3),
+	ARITH_PRECEDENCE(ARITH_GE, 3),
+	ARITH_PRECEDENCE(ARITH_EQ, 4),
+	ARITH_PRECEDENCE(ARITH_NE, 4),
+	ARITH_PRECEDENCE(ARITH_BAND, 5),
+	ARITH_PRECEDENCE(ARITH_BXOR, 6),
+	ARITH_PRECEDENCE(ARITH_BOR, 7),
+};
+
+#define ARITH_MAX_PREC 8
+
+int letcmd(int, char **);
+
+static __attribute__((noreturn)) void yyerror(const char *s)
+{
+	error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
+	/* NOTREACHED */
+}
+
+static arith_t arith_lookupvarint(char *varname)
+{
+	const char *str;
+	char *p;
+	arith_t result;
+
+	str = lookupvar(varname);
+	if (uflag && str == NULL)
+		yyerror("variable not set");
+	if (str == NULL || *str == '\0')
+		str = "0";
+	errno = 0;
+	result = strtoarith_t(str, &p);
+	if (errno != 0 || *p != '\0')
+		yyerror("variable conversion error");
+	return result;
+}
+
+static inline int arith_prec(int op)
+{
+	return prec[op - ARITH_BINOP_MIN];
+}
+
+static inline int higher_prec(int op1, int op2)
+{
+	return arith_prec(op1) < arith_prec(op2);
+}
+
+static arith_t do_binop(int op, arith_t a, arith_t b)
+{
+
+	switch (op) {
+	default:
+	case ARITH_REM:
+	case ARITH_DIV:
+		if (!b)
+			yyerror("division by zero");
+		if (a == ARITH_MIN && b == -1)
+			yyerror("divide error");
+		return op == ARITH_REM ? a % b : a / b;
+	case ARITH_MUL:
+		return (uintmax_t)a * (uintmax_t)b;
+	case ARITH_ADD:
+		return (uintmax_t)a + (uintmax_t)b;
+	case ARITH_SUB:
+		return (uintmax_t)a - (uintmax_t)b;
+	case ARITH_LSHIFT:
+		return (uintmax_t)a << (b & (sizeof(uintmax_t) * CHAR_BIT - 1));
+	case ARITH_RSHIFT:
+		return a >> (b & (sizeof(uintmax_t) * CHAR_BIT - 1));
+	case ARITH_LT:
+		return a < b;
+	case ARITH_LE:
+		return a <= b;
+	case ARITH_GT:
+		return a > b;
+	case ARITH_GE:
+		return a >= b;
+	case ARITH_EQ:
+		return a == b;
+	case ARITH_NE:
+		return a != b;
+	case ARITH_BAND:
+		return a & b;
+	case ARITH_BXOR:
+		return a ^ b;
+	case ARITH_BOR:
+		return a | b;
+	}
+}
+
+static arith_t assignment(int var, int noeval);
+
+static arith_t primary(int token, union yystype *val, int op, int noeval)
+{
+	arith_t result;
+
+again:
+	switch (token) {
+	case ARITH_LPAREN:
+		result = assignment(op, noeval);
+		if (last_token != ARITH_RPAREN)
+			yyerror("expecting ')'");
+		last_token = yylex();
+		return result;
+	case ARITH_NUM:
+		last_token = op;
+		return val->val;
+	case ARITH_VAR:
+		last_token = op;
+		return noeval ? val->val : arith_lookupvarint(val->name);
+	case ARITH_ADD:
+		token = op;
+		*val = yylval;
+		op = yylex();
+		goto again;
+	case ARITH_SUB:
+		*val = yylval;
+		return -primary(op, val, yylex(), noeval);
+	case ARITH_NOT:
+		*val = yylval;
+		return !primary(op, val, yylex(), noeval);
+	case ARITH_BNOT:
+		*val = yylval;
+		return ~primary(op, val, yylex(), noeval);
+	default:
+		yyerror("expecting primary");
+	}
+}
+
+static arith_t binop2(arith_t a, int op, int precedence, int noeval)
+{
+	for (;;) {
+		union yystype val;
+		arith_t b;
+		int op2;
+		int token;
+
+		token = yylex();
+		val = yylval;
+
+		b = primary(token, &val, yylex(), noeval);
+
+		op2 = last_token;
+		if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX &&
+		    higher_prec(op2, op)) {
+			b = binop2(b, op2, arith_prec(op), noeval);
+			op2 = last_token;
+		}
+
+		a = noeval ? b : do_binop(op, a, b);
+
+		if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX ||
+		    arith_prec(op2) >= precedence)
+			return a;
+
+		op = op2;
+	}
+}
+
+static arith_t binop(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = primary(token, val, op, noeval);
+
+	op = last_token;
+	if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX)
+		return a;
+
+	return binop2(a, op, ARITH_MAX_PREC, noeval);
+}
+
+static arith_t and(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = binop(token, val, op, noeval);
+	arith_t b;
+
+	op = last_token;
+	if (op != ARITH_AND)
+		return a;
+
+	token = yylex();
+	*val = yylval;
+
+	b = and(token, val, yylex(), noeval | !a);
+
+	return a && b;
+}
+
+static arith_t or(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = and(token, val, op, noeval);
+	arith_t b;
+
+	op = last_token;
+	if (op != ARITH_OR)
+		return a;
+
+	token = yylex();
+	*val = yylval;
+
+	b = or(token, val, yylex(), noeval | !!a);
+
+	return a || b;
+}
+
+static arith_t cond(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = or(token, val, op, noeval);
+	arith_t b;
+	arith_t c;
+
+	if (last_token != ARITH_QMARK)
+		return a;
+
+	b = assignment(yylex(), noeval | !a);
+
+	if (last_token != ARITH_COLON)
+		yyerror("expecting ':'");
+
+	token = yylex();
+	*val = yylval;
+
+	c = cond(token, val, yylex(), noeval | !!a);
+
+	return a ? b : c;
+}
+
+static arith_t assignment(int var, int noeval)
+{
+	union yystype val = yylval;
+	int op = yylex();
+	arith_t result;
+	char sresult[DIGITS(result) + 1];
+
+	if (var != ARITH_VAR)
+		return cond(var, &val, op, noeval);
+
+	if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX))
+		return cond(var, &val, op, noeval);
+
+	result = assignment(yylex(), noeval);
+	if (noeval)
+		return result;
+
+	if (op != ARITH_ASS)
+		result = do_binop(op - 11, arith_lookupvarint(val.name), result);
+	snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR, result);
+	setvar(val.name, sresult, 0);
+	return result;
+}
+
+arith_t arith(const char *s)
+{
+	struct stackmark smark;
+	arith_t result;
+
+	setstackmark(&smark);
+
+	arith_buf = arith_startbuf = s;
+
+	result = assignment(yylex(), 0);
+
+	if (last_token)
+		yyerror("expecting EOF");
+
+	popstackmark(&smark);
+
+	return result;
+}
+
+/*
+ *  The exp(1) builtin.
+ */
+int
+letcmd(int argc, char **argv)
+{
+	const char *p;
+	char *concat;
+	char **ap;
+	arith_t i;
+
+	if (argc > 1) {
+		p = argv[1];
+		if (argc > 2) {
+			/*
+			 * Concatenate arguments.
+			 */
+			STARTSTACKSTR(concat);
+			ap = argv + 2;
+			for (;;) {
+				while (*p)
+					STPUTC(*p++, concat);
+				if ((p = *ap++) == NULL)
+					break;
+				STPUTC(' ', concat);
+			}
+			STPUTC('\0', concat);
+			p = grabstackstr(concat);
+		}
+	} else
+		p = "";
+
+	i = arith(p);
+
+	out1fmt(ARITH_FORMAT_STR "\n", i);
+	return !i;
+}
diff --git a/bin/1sh/arith_yacc.h b/bin/1sh/arith_yacc.h
new file mode 100644
index 00000000..433481bb
--- /dev/null
+++ b/bin/1sh/arith_yacc.h
@@ -0,0 +1,94 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2007
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: releng/12.1/bin/sh/arith_yacc.h 345117 2019-03-13 21:53:10Z jilles $
+ */
+
+#define ARITH_ASS 1
+
+#define ARITH_OR 2
+#define ARITH_AND 3
+#define ARITH_BAD 4
+#define ARITH_NUM 5
+#define ARITH_VAR 6
+#define ARITH_NOT 7
+
+#define ARITH_BINOP_MIN 8
+#define ARITH_LE 8
+#define ARITH_GE 9
+#define ARITH_LT 10
+#define ARITH_GT 11
+#define ARITH_EQ 12
+#define ARITH_REM 13
+#define ARITH_BAND 14
+#define ARITH_LSHIFT 15
+#define ARITH_RSHIFT 16
+#define ARITH_MUL 17
+#define ARITH_ADD 18
+#define ARITH_BOR 19
+#define ARITH_SUB 20
+#define ARITH_BXOR 21
+#define ARITH_DIV 22
+#define ARITH_NE 23
+#define ARITH_BINOP_MAX 24
+
+#define ARITH_ASS_MIN 24
+#define ARITH_REMASS 24
+#define ARITH_BANDASS 25
+#define ARITH_LSHIFTASS 26
+#define ARITH_RSHIFTASS 27
+#define ARITH_MULASS 28
+#define ARITH_ADDASS 29
+#define ARITH_BORASS 30
+#define ARITH_SUBASS 31
+#define ARITH_BXORASS 32
+#define ARITH_DIVASS 33
+#define ARITH_ASS_MAX 34
+
+#define ARITH_LPAREN 34
+#define ARITH_RPAREN 35
+#define ARITH_BNOT 36
+#define ARITH_QMARK 37
+#define ARITH_COLON 38
+
+extern const char *arith_buf;
+
+union yystype {
+	arith_t val;
+	char *name;
+};
+
+extern union yystype yylval;
+
+arith_t strtoarith_t(const char *restrict nptr, char **restrict endptr);
+int yylex(void);
diff --git a/bin/1sh/arith_yylex.c b/bin/1sh/arith_yylex.c
new file mode 100644
index 00000000..da3a4f70
--- /dev/null
+++ b/bin/1sh/arith_yylex.c
@@ -0,0 +1,276 @@
+/*-
+ * Copyright (c) 2002
+ *	Herbert Xu.
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/arith_yylex.c 345117 2019-03-13 21:53:10Z jilles $ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include "shell.h"
+#include "arith_yacc.h"
+#include "expand.h"
+#include "error.h"
+#include "memalloc.h"
+#include "parser.h"
+#include "syntax.h"
+
+#if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ
+#error Arithmetic tokens are out of order.
+#endif
+
+arith_t
+strtoarith_t(const char *restrict nptr, char **restrict endptr)
+{
+	arith_t val;
+
+	while (isspace((unsigned char)*nptr))
+		nptr++;
+	switch (*nptr) {
+		case '-':
+			return strtoimax(nptr, endptr, 0);
+		case '0':
+			return (arith_t)strtoumax(nptr, endptr, 0);
+		default:
+			val = (arith_t)strtoumax(nptr, endptr, 0);
+			if (val >= 0)
+				return val;
+			else if (val == ARITH_MIN) {
+				errno = ERANGE;
+				return ARITH_MIN;
+			} else {
+				errno = ERANGE;
+				return ARITH_MAX;
+			}
+	}
+}
+
+int
+yylex(void)
+{
+	int value;
+	const char *buf = arith_buf;
+	char *end;
+	const char *p;
+
+	for (;;) {
+		value = *buf;
+		switch (value) {
+		case ' ':
+		case '\t':
+		case '\n':
+			buf++;
+			continue;
+		default:
+			return ARITH_BAD;
+		case '0':
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+		case '8':
+		case '9':
+			yylval.val = strtoarith_t(buf, &end);
+			arith_buf = end;
+			return ARITH_NUM;
+		case 'A':
+		case 'B':
+		case 'C':
+		case 'D':
+		case 'E':
+		case 'F':
+		case 'G':
+		case 'H':
+		case 'I':
+		case 'J':
+		case 'K':
+		case 'L':
+		case 'M':
+		case 'N':
+		case 'O':
+		case 'P':
+		case 'Q':
+		case 'R':
+		case 'S':
+		case 'T':
+		case 'U':
+		case 'V':
+		case 'W':
+		case 'X':
+		case 'Y':
+		case 'Z':
+		case '_':
+		case 'a':
+		case 'b':
+		case 'c':
+		case 'd':
+		case 'e':
+		case 'f':
+		case 'g':
+		case 'h':
+		case 'i':
+		case 'j':
+		case 'k':
+		case 'l':
+		case 'm':
+		case 'n':
+		case 'o':
+		case 'p':
+		case 'q':
+		case 'r':
+		case 's':
+		case 't':
+		case 'u':
+		case 'v':
+		case 'w':
+		case 'x':
+		case 'y':
+		case 'z':
+			p = buf;
+			while (buf++, is_in_name(*buf))
+				;
+			yylval.name = stalloc(buf - p + 1);
+			memcpy(yylval.name, p, buf - p);
+			yylval.name[buf - p] = '\0';
+			value = ARITH_VAR;
+			goto out;
+		case '=':
+			value += ARITH_ASS - '=';
+checkeq:
+			buf++;
+checkeqcur:
+			if (*buf != '=')
+				goto out;
+			value += 11;
+			break;
+		case '>':
+			switch (*++buf) {
+			case '=':
+				value += ARITH_GE - '>';
+				break;
+			case '>':
+				value += ARITH_RSHIFT - '>';
+				goto checkeq;
+			default:
+				value += ARITH_GT - '>';
+				goto out;
+			}
+			break;
+		case '<':
+			switch (*++buf) {
+			case '=':
+				value += ARITH_LE - '<';
+				break;
+			case '<':
+				value += ARITH_LSHIFT - '<';
+				goto checkeq;
+			default:
+				value += ARITH_LT - '<';
+				goto out;
+			}
+			break;
+		case '|':
+			if (*++buf != '|') {
+				value += ARITH_BOR - '|';
+				goto checkeqcur;
+			}
+			value += ARITH_OR - '|';
+			break;
+		case '&':
+			if (*++buf != '&') {
+				value += ARITH_BAND - '&';
+				goto checkeqcur;
+			}
+			value += ARITH_AND - '&';
+			break;
+		case '!':
+			if (*++buf != '=') {
+				value += ARITH_NOT - '!';
+				goto out;
+			}
+			value += ARITH_NE - '!';
+			break;
+		case 0:
+			goto out;
+		case '(':
+			value += ARITH_LPAREN - '(';
+			break;
+		case ')':
+			value += ARITH_RPAREN - ')';
+			break;
+		case '*':
+			value += ARITH_MUL - '*';
+			goto checkeq;
+		case '/':
+			value += ARITH_DIV - '/';
+			goto checkeq;
+		case '%':
+			value += ARITH_REM - '%';
+			goto checkeq;
+		case '+':
+			if (buf[1] == '+')
+				return ARITH_BAD;
+			value += ARITH_ADD - '+';
+			goto checkeq;
+		case '-':
+			if (buf[1] == '-')
+				return ARITH_BAD;
+			value += ARITH_SUB - '-';
+			goto checkeq;
+		case '~':
+			value += ARITH_BNOT - '~';
+			break;
+		case '^':
+			value += ARITH_BXOR - '^';
+			goto checkeq;
+		case '?':
+			value += ARITH_QMARK - '?';
+			break;
+		case ':':
+			value += ARITH_COLON - ':';
+			break;
+		}
+		break;
+	}
+
+	buf++;
+out:
+	arith_buf = buf;
+	return value;
+}
diff --git a/bin/1sh/bltin.h b/bin/1sh/bltin.h
new file mode 100644
index 00000000..3d2cb4d3
--- /dev/null
+++ b/bin/1sh/bltin.h
@@ -0,0 +1,81 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)bltin.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/bltin/bltin.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+/*
+ * This file is included by programs which are optionally built into the
+ * shell.  If SHELL is defined, we try to map the standard UNIX library
+ * routines to ash routines using defines.
+ */
+
+#include "shell.h"
+#include "mystring.h"
+#ifdef SHELL
+#include "error.h"
+#include "output.h"
+#include "builtins.h"
+#define FILE struct output
+#undef stdout
+#define stdout out1
+#undef stderr
+#define stderr out2
+#define printf out1fmt
+#undef putc
+#define putc(c, file)	outc(c, file)
+#undef putchar
+#define putchar(c)	out1c(c)
+#define fprintf outfmt
+#define fputs outstr
+#define fwrite(ptr, size, nmemb, file) outbin(ptr, (size) * (nmemb), file)
+#define fflush flushout
+#define INITARGS(argv)
+#define warnx warning
+#define warn(fmt, ...) warning(fmt ": %s", __VA_ARGS__, strerror(errno))
+#define errx(exitstatus, ...) error(__VA_ARGS__)
+
+#else
+#undef NULL
+#include <stdio.h>
+#undef main
+#define INITARGS(argv)	if ((commandname = argv[0]) == NULL) {fputs("Argc is zero\n", stderr); exit(2);} else
+#endif
+
+#include <unistd.h>
+
+pointer stalloc(int);
+int killjob(const char *, int);
+
+extern char *commandname;
diff --git a/bin/1sh/builtins.def b/bin/1sh/builtins.def
new file mode 100644
index 00000000..5986a5a6
--- /dev/null
+++ b/bin/1sh/builtins.def
@@ -0,0 +1,96 @@
+#!/bin/sh -
+
+#-
+# Copyright (c) 1991, 1993
+#	The Regents of the University of California.  All rights reserved.
+#
+# This code is derived from software contributed to Berkeley by
+# Kenneth Almquist.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. Neither the name of the University nor the names of its contributors
+#    may be used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+#	@(#)builtins.def	8.4 (Berkeley) 5/4/95
+# $FreeBSD: releng/12.1/bin/sh/builtins.def 319576 2017-06-04 21:02:48Z bdrewery $
+
+#
+# This file lists all the builtin commands.  The first column is the name
+# of a C routine.
+# The -j flag specifies that this command is to be excluded from systems
+# without job control.
+# The -h flag specifies that this command is to be excluded from systems
+# based on the NO_HISTORY compile-time symbol.
+# The -n flag specifies that this command can safely be run in the same
+# process when it is the only command in a command substitution.  Some
+# commands have special logic defined in safe_builtin().
+# The -s flag specifies that this is a POSIX 'special built-in' command.
+# The rest of the line specifies the command name or names used to run the
+# command.  The entry for bltincmd, which is run when the user does not specify
+# a command, must come first.
+#
+# NOTE: bltincmd must come first!
+
+bltincmd -n	builtin
+aliascmd	alias
+bgcmd -j	bg
+bindcmd		bind
+breakcmd	-s break -s continue
+cdcmd		cd chdir
+commandcmd -n	command
+dotcmd		-s .
+echocmd -n	echo
+evalcmd		-s eval
+execcmd		-s exec
+exitcmd		-s exit
+letcmd		let
+exportcmd	-s export -s readonly
+#exprcmd		expr
+falsecmd -n	false
+fgcmd -j	fg
+freebsd_wordexpcmd	freebsd_wordexp
+getoptscmd	getopts
+hashcmd		hash
+histcmd -h	fc
+jobidcmd -n	jobid
+jobscmd -n	jobs
+killcmd -n	kill
+localcmd	local
+printfcmd -n	printf
+pwdcmd -n	pwd
+readcmd		read
+returncmd	-s return
+setcmd		-s set
+setvarcmd	setvar
+shiftcmd	-s shift
+testcmd -n	test [
+timescmd -n	-s times
+trapcmd		-s trap
+truecmd -n	-s : true
+typecmd -n	type
+ulimitcmd	ulimit
+umaskcmd	umask
+unaliascmd	unalias
+unsetcmd	-s unset
+waitcmd		wait
+wordexpcmd	wordexp
diff --git a/bin/1sh/cd.c b/bin/1sh/cd.c
new file mode 100644
index 00000000..61bb60cf
--- /dev/null
+++ b/bin/1sh/cd.c
@@ -0,0 +1,430 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)cd.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/cd.c 336320 2018-07-15 21:55:17Z jilles $ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <limits.h>
+
+/*
+ * The cd and pwd commands.
+ */
+
+#include "shell.h"
+#include "var.h"
+#include "nodes.h"	/* for jobs.h */
+#include "jobs.h"
+#include "options.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "exec.h"
+#include "redir.h"
+#include "mystring.h"
+#include "show.h"
+#include "cd.h"
+#include "builtins.h"
+
+static int cdlogical(char *);
+static int cdphysical(char *);
+static int docd(char *, int, int);
+static char *getcomponent(char **);
+static char *findcwd(char *);
+static void updatepwd(char *);
+static char *getpwd(void);
+static char *getpwd2(void);
+
+static char *curdir = NULL;	/* current working directory */
+
+int
+cdcmd(int argc __unused, char **argv __unused)
+{
+	const char *dest;
+	const char *path;
+	char *p;
+	struct stat statb;
+	int ch, phys, print = 0, getcwderr = 0;
+	int rc;
+	int errno1 = ENOENT;
+
+	phys = Pflag;
+	while ((ch = nextopt("eLP")) != '\0') {
+		switch (ch) {
+		case 'e':
+			getcwderr = 1;
+			break;
+		case 'L':
+			phys = 0;
+			break;
+		case 'P':
+			phys = 1;
+			break;
+		}
+	}
+
+	if (*argptr != NULL && argptr[1] != NULL)
+		error("too many arguments");
+
+	if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
+		error("HOME not set");
+	if (*dest == '\0')
+		dest = ".";
+	if (dest[0] == '-' && dest[1] == '\0') {
+		dest = bltinlookup("OLDPWD", 1);
+		if (dest == NULL)
+			error("OLDPWD not set");
+		print = 1;
+	}
+	if (dest[0] == '/' ||
+	    (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
+	    (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
+	    (path = bltinlookup("CDPATH", 1)) == NULL)
+		path = "";
+	while ((p = padvance(&path, NULL, dest)) != NULL) {
+		if (stat(p, &statb) < 0) {
+			if (errno != ENOENT)
+				errno1 = errno;
+		} else if (!S_ISDIR(statb.st_mode))
+			errno1 = ENOTDIR;
+		else {
+			if (!print) {
+				/*
+				 * XXX - rethink
+				 */
+				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
+					print = strcmp(p + 2, dest);
+				else
+					print = strcmp(p, dest);
+			}
+			rc = docd(p, print, phys);
+			if (rc >= 0)
+				return getcwderr ? rc : 0;
+			if (errno != ENOENT)
+				errno1 = errno;
+		}
+	}
+	error("%s: %s", dest, strerror(errno1));
+	/*NOTREACHED*/
+	return 0;
+}
+
+
+/*
+ * Actually change the directory.  In an interactive shell, print the
+ * directory name if "print" is nonzero.
+ */
+static int
+docd(char *dest, int print, int phys)
+{
+	int rc;
+
+	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
+
+	/* If logical cd fails, fall back to physical. */
+	if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
+		return (-1);
+
+	if (print && iflag && curdir) {
+		out1fmt("%s\n", curdir);
+		/*
+		 * Ignore write errors to preserve the invariant that the
+		 * current directory is changed iff the exit status is 0
+		 * (or 1 if -e was given and the full pathname could not be
+		 * determined).
+		 */
+		flushout(out1);
+		outclearerror(out1);
+	}
+
+	return (rc);
+}
+
+static int
+cdlogical(char *dest)
+{
+	char *p;
+	char *q;
+	char *component;
+	char *path;
+	struct stat statb;
+	int first;
+	int badstat;
+
+	/*
+	 *  Check each component of the path. If we find a symlink or
+	 *  something we can't stat, clear curdir to force a getcwd()
+	 *  next time we get the value of the current directory.
+	 */
+	badstat = 0;
+	path = stsavestr(dest);
+	STARTSTACKSTR(p);
+	if (*dest == '/') {
+		STPUTC('/', p);
+		path++;
+	}
+	first = 1;
+	while ((q = getcomponent(&path)) != NULL) {
+		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
+			continue;
+		if (! first)
+			STPUTC('/', p);
+		first = 0;
+		component = q;
+		STPUTS(q, p);
+		if (equal(component, ".."))
+			continue;
+		STACKSTRNUL(p);
+		if (lstat(stackblock(), &statb) < 0) {
+			badstat = 1;
+			break;
+		}
+	}
+
+	INTOFF;
+	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
+		INTON;
+		return (-1);
+	}
+	updatepwd(p);
+	INTON;
+	return (0);
+}
+
+static int
+cdphysical(char *dest)
+{
+	char *p;
+	int rc = 0;
+
+	INTOFF;
+	if (chdir(dest) < 0) {
+		INTON;
+		return (-1);
+	}
+	p = findcwd(NULL);
+	if (p == NULL) {
+		warning("warning: failed to get name of current directory");
+		rc = 1;
+	}
+	updatepwd(p);
+	INTON;
+	return (rc);
+}
+
+/*
+ * Get the next component of the path name pointed to by *path.
+ * This routine overwrites *path and the string pointed to by it.
+ */
+static char *
+getcomponent(char **path)
+{
+	char *p;
+	char *start;
+
+	if ((p = *path) == NULL)
+		return NULL;
+	start = *path;
+	while (*p != '/' && *p != '\0')
+		p++;
+	if (*p == '\0') {
+		*path = NULL;
+	} else {
+		*p++ = '\0';
+		*path = p;
+	}
+	return start;
+}
+
+
+static char *
+findcwd(char *dir)
+{
+	char *new;
+	char *p;
+	char *path;
+
+	/*
+	 * If our argument is NULL, we don't know the current directory
+	 * any more because we traversed a symbolic link or something
+	 * we couldn't stat().
+	 */
+	if (dir == NULL || curdir == NULL)
+		return getpwd2();
+	path = stsavestr(dir);
+	STARTSTACKSTR(new);
+	if (*dir != '/') {
+		STPUTS(curdir, new);
+		if (STTOPC(new) == '/')
+			STUNPUTC(new);
+	}
+	while ((p = getcomponent(&path)) != NULL) {
+		if (equal(p, "..")) {
+			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
+		} else if (*p != '\0' && ! equal(p, ".")) {
+			STPUTC('/', new);
+			STPUTS(p, new);
+		}
+	}
+	if (new == stackblock())
+		STPUTC('/', new);
+	STACKSTRNUL(new);
+	return stackblock();
+}
+
+/*
+ * Update curdir (the name of the current directory) in response to a
+ * cd command.  We also call hashcd to let the routines in exec.c know
+ * that the current directory has changed.
+ */
+static void
+updatepwd(char *dir)
+{
+	char *prevdir;
+
+	hashcd();				/* update command hash table */
+
+	setvar("PWD", dir, VEXPORT);
+	setvar("OLDPWD", curdir, VEXPORT);
+	prevdir = curdir;
+	curdir = dir ? savestr(dir) : NULL;
+	ckfree(prevdir);
+}
+
+int
+pwdcmd(int argc __unused, char **argv __unused)
+{
+	char *p;
+	int ch, phys;
+
+	phys = Pflag;
+	while ((ch = nextopt("LP")) != '\0') {
+		switch (ch) {
+		case 'L':
+			phys = 0;
+			break;
+		case 'P':
+			phys = 1;
+			break;
+		}
+	}
+
+	if (*argptr != NULL)
+		error("too many arguments");
+
+	if (!phys && getpwd()) {
+		out1str(curdir);
+		out1c('\n');
+	} else {
+		if ((p = getpwd2()) == NULL)
+			error(".: %s", strerror(errno));
+		out1str(p);
+		out1c('\n');
+	}
+
+	return 0;
+}
+
+/*
+ * Get the current directory and cache the result in curdir.
+ */
+static char *
+getpwd(void)
+{
+	char *p;
+
+	if (curdir)
+		return curdir;
+
+	p = getpwd2();
+	if (p != NULL)
+		curdir = savestr(p);
+
+	return curdir;
+}
+
+#define MAXPWD 256
+
+/*
+ * Return the current directory.
+ */
+static char *
+getpwd2(void)
+{
+	char *pwd;
+	int i;
+
+	for (i = MAXPWD;; i *= 2) {
+		pwd = stalloc(i);
+		if (getcwd(pwd, i) != NULL)
+			return pwd;
+		stunalloc(pwd);
+		if (errno != ERANGE)
+			break;
+	}
+
+	return NULL;
+}
+
+/*
+ * Initialize PWD in a new shell.
+ * If the shell is interactive, we need to warn if this fails.
+ */
+void
+pwd_init(int warn)
+{
+	char *pwd;
+	struct stat stdot, stpwd;
+
+	pwd = lookupvar("PWD");
+	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
+	    stat(pwd, &stpwd) != -1 &&
+	    stdot.st_dev == stpwd.st_dev &&
+	    stdot.st_ino == stpwd.st_ino) {
+		if (curdir)
+			ckfree(curdir);
+		curdir = savestr(pwd);
+	}
+	if (getpwd() == NULL && warn)
+		out2fmt_flush("sh: cannot determine working directory\n");
+	setvar("PWD", curdir, VEXPORT);
+}
diff --git a/bin/1sh/cd.h b/bin/1sh/cd.h
new file mode 100644
index 00000000..dfa5c3e5
--- /dev/null
+++ b/bin/1sh/cd.h
@@ -0,0 +1,32 @@
+/*-
+ * Copyright (c) 1995
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: releng/12.1/bin/sh/cd.h 314436 2017-02-28 23:42:47Z imp $
+ */
+
+void	 pwd_init(int);
diff --git a/bin/1sh/echo.c b/bin/1sh/echo.c
new file mode 100644
index 00000000..5fd50f59
--- /dev/null
+++ b/bin/1sh/echo.c
@@ -0,0 +1,109 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)echo.c	8.2 (Berkeley) 5/4/95
+ */
+
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/bltin/echo.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+/*
+ * Echo command.
+ */
+
+#define main echocmd
+
+#include "bltin.h"
+
+/* #define eflag 1 */
+
+int
+main(int argc, char *argv[])
+{
+	char **ap;
+	char *p;
+	char c;
+	int count;
+	int nflag = 0;
+#ifndef eflag
+	int eflag = 0;
+#endif
+
+	ap = argv;
+	if (argc)
+		ap++;
+	if ((p = *ap) != NULL) {
+		if (equal(p, "-n")) {
+			nflag++;
+			ap++;
+		} else if (equal(p, "-e")) {
+#ifndef eflag
+			eflag++;
+#endif
+			ap++;
+		}
+	}
+	while ((p = *ap++) != NULL) {
+		while ((c = *p++) != '\0') {
+			if (c == '\\' && eflag) {
+				switch (*p++) {
+				case 'a':  c = '\a';  break;
+				case 'b':  c = '\b';  break;
+				case 'c':  return 0;		/* exit */
+				case 'e':  c = '\033';  break;
+				case 'f':  c = '\f';  break;
+				case 'n':  c = '\n';  break;
+				case 'r':  c = '\r';  break;
+				case 't':  c = '\t';  break;
+				case 'v':  c = '\v';  break;
+				case '\\':  break;		/* c = '\\' */
+				case '0':
+					c = 0;
+					count = 3;
+					while (--count >= 0 && (unsigned)(*p - '0') < 8)
+						c = (c << 3) + (*p++ - '0');
+					break;
+				default:
+					p--;
+					break;
+				}
+			}
+			putchar(c);
+		}
+		if (*ap)
+			putchar(' ');
+	}
+	if (! nflag)
+		putchar('\n');
+	return 0;
+}
diff --git a/bin/1sh/error.c b/bin/1sh/error.c
new file mode 100644
index 00000000..57c10fae
--- /dev/null
+++ b/bin/1sh/error.c
@@ -0,0 +1,199 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)error.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/error.c 314436 2017-02-28 23:42:47Z imp $ */
+
+/*
+ * Errors and exceptions.
+ */
+
+#include "shell.h"
+#include "eval.h"
+#include "main.h"
+#include "options.h"
+#include "output.h"
+#include "error.h"
+#include "nodes.h" /* show.h needs nodes.h */
+#include "show.h"
+#include "trap.h"
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+
+/*
+ * Code to handle exceptions in C.
+ */
+
+struct jmploc *handler;
+volatile sig_atomic_t exception;
+volatile sig_atomic_t suppressint;
+volatile sig_atomic_t intpending;
+
+
+static void exverror(int, const char *, va_list) __attribute__((format(printf, 2, 0))) __attribute__((noreturn));
+
+/*
+ * Called to raise an exception.  Since C doesn't include exceptions, we
+ * just do a longjmp to the exception handler.  The type of exception is
+ * stored in the global variable "exception".
+ *
+ * Interrupts are disabled; they should be reenabled when the exception is
+ * caught.
+ */
+
+void
+exraise(int e)
+{
+	INTOFF;
+	if (handler == NULL)
+		abort();
+	exception = e;
+	longjmp(handler->loc, 1);
+}
+
+
+/*
+ * Called from trap.c when a SIGINT is received and not suppressed, or when
+ * an interrupt is pending and interrupts are re-enabled using INTON.
+ * (If the user specifies that SIGINT is to be trapped or ignored using the
+ * trap builtin, then this routine is not called.)  Suppressint is nonzero
+ * when interrupts are held using the INTOFF macro.  If SIGINTs are not
+ * suppressed and the shell is not a root shell, then we want to be
+ * terminated if we get here, as if we were terminated directly by a SIGINT.
+ * Arrange for this here.
+ */
+
+void
+onint(void)
+{
+	sigset_t sigs;
+
+	intpending = 0;
+	sigemptyset(&sigs);
+	sigprocmask(SIG_SETMASK, &sigs, NULL);
+
+	/*
+	 * This doesn't seem to be needed, since main() emits a newline.
+	 */
+#if 0
+	if (tcgetpgrp(0) == getpid())
+		write(STDERR_FILENO, "\n", 1);
+#endif
+	if (rootshell && iflag)
+		exraise(EXINT);
+	else {
+		signal(SIGINT, SIG_DFL);
+		kill(getpid(), SIGINT);
+		_exit(128 + SIGINT);
+	}
+}
+
+
+static void
+vwarning(const char *msg, va_list ap)
+{
+	if (commandname)
+		outfmt(out2, "%s: ", commandname);
+	else if (arg0)
+		outfmt(out2, "%s: ", arg0);
+	doformat(out2, msg, ap);
+	out2fmt_flush("\n");
+}
+
+
+void
+warning(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	vwarning(msg, ap);
+	va_end(ap);
+}
+
+
+/*
+ * Exverror is called to raise the error exception.  If the first argument
+ * is not NULL then error prints an error message using printf style
+ * formatting.  It then raises the error exception.
+ */
+static void
+exverror(int cond, const char *msg, va_list ap)
+{
+	/*
+	 * An interrupt trumps an error.  Certain places catch error
+	 * exceptions or transform them to a plain nonzero exit code
+	 * in child processes, and if an error exception can be handled,
+	 * an interrupt can be handled as well.
+	 *
+	 * exraise() will disable interrupts for the exception handler.
+	 */
+	FORCEINTON;
+
+#ifdef DEBUG
+	if (msg)
+		TRACE(("exverror(%d, \"%s\") pid=%d\n", cond, msg, getpid()));
+	else
+		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));
+#endif
+	if (msg)
+		vwarning(msg, ap);
+	flushall();
+	exraise(cond);
+}
+
+
+void
+error(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	exverror(EXERROR, msg, ap);
+	va_end(ap);
+}
+
+
+void
+exerror(int cond, const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	exverror(cond, msg, ap);
+	va_end(ap);
+}
diff --git a/bin/1sh/error.h b/bin/1sh/error.h
new file mode 100644
index 00000000..0401598f
--- /dev/null
+++ b/bin/1sh/error.h
@@ -0,0 +1,95 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)error.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/error.h 319591 2017-06-04 21:58:02Z jilles $
+ */
+
+/*
+ * We enclose jmp_buf in a structure so that we can declare pointers to
+ * jump locations.  The global variable handler contains the location to
+ * jump to when an exception occurs, and the global variable exception
+ * contains a code identifying the exception.  To implement nested
+ * exception handlers, the user should save the value of handler on entry
+ * to an inner scope, set handler to point to a jmploc structure for the
+ * inner scope, and restore handler on exit from the scope.
+ */
+
+#include <setjmp.h>
+#include <signal.h>
+
+struct jmploc {
+	jmp_buf loc;
+};
+
+extern struct jmploc *handler;
+extern volatile sig_atomic_t exception;
+
+/* exceptions */
+#define EXINT 0		/* SIGINT received */
+#define EXERROR 1	/* a generic error */
+#define EXEXEC 2	/* command execution failed */
+#define EXEXIT 3	/* call exitshell(exitstatus) */
+
+
+/*
+ * These macros allow the user to suspend the handling of interrupt signals
+ * over a period of time.  This is similar to SIGHOLD to or sigblock, but
+ * much more efficient and portable.  (But hacking the kernel is so much
+ * more fun than worrying about efficiency and portability. :-))
+ */
+
+extern volatile sig_atomic_t suppressint;
+extern volatile sig_atomic_t intpending;
+
+#define INTOFF suppressint++
+#define INTON { if (--suppressint == 0 && intpending) onint(); }
+#define is_int_on() suppressint
+#define SETINTON(s) do { suppressint = (s); if (suppressint == 0 && intpending) onint(); } while (0)
+#define FORCEINTON {suppressint = 0; if (intpending) onint();}
+#define SET_PENDING_INT intpending = 1
+#define CLEAR_PENDING_INT intpending = 0
+#define int_pending() intpending
+
+void exraise(int) __attribute__((noreturn));
+void onint(void) __attribute__((noreturn));
+void warning(const char *, ...) __attribute__((format(printf, 1, 2)));
+void error(const char *, ...) __attribute__((format(printf, 1, 2))) __attribute__((noreturn));
+void exerror(int, const char *, ...) __attribute__((format(printf, 2, 3))) __attribute__((noreturn));
+
+
+/*
+ * BSD setjmp saves the signal mask, which violates ANSI C and takes time,
+ * so we use _setjmp instead.
+ */
+
+#define setjmp(jmploc)	_setjmp(jmploc)
+#define longjmp(jmploc, val)	_longjmp(jmploc, val)
diff --git a/bin/1sh/eval.c b/bin/1sh/eval.c
new file mode 100644
index 00000000..f4baf39e
--- /dev/null
+++ b/bin/1sh/eval.c
@@ -0,0 +1,1381 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)eval.c	8.9 (Berkeley) 6/8/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/eval.c 327212 2017-12-26 16:23:18Z jilles $ */
+
+#include <paths.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/resource.h>
+#include <errno.h>
+
+/*
+ * Evaluate a command.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "syntax.h"
+#include "expand.h"
+#include "parser.h"
+#include "jobs.h"
+#include "eval.h"
+#include "builtins.h"
+#include "options.h"
+#include "exec.h"
+#include "redir.h"
+#include "input.h"
+#include "output.h"
+#include "trap.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "show.h"
+#include "mystring.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+
+int evalskip;			/* set if we are skipping commands */
+int skipcount;			/* number of levels to skip */
+static int loopnest;		/* current loop nesting level */
+int funcnest;			/* depth of function calls */
+static int builtin_flags;	/* evalcommand flags for builtins */
+
+
+char *commandname;
+struct arglist *cmdenviron;
+int exitstatus;			/* exit status of last command */
+int oexitstatus;		/* saved exit status */
+
+
+static void evalloop(union node *, int);
+static void evalfor(union node *, int);
+static union node *evalcase(union node *);
+static void evalsubshell(union node *, int);
+static void evalredir(union node *, int);
+static void exphere(union node *, struct arglist *);
+static void expredir(union node *);
+static void evalpipe(union node *);
+static int is_valid_fast_cmdsubst(union node *n);
+static void evalcommand(union node *, int, struct backcmd *);
+static void prehash(union node *);
+
+
+/*
+ * Called to reset things after an exception.
+ */
+
+void
+reseteval(void)
+{
+	evalskip = 0;
+	loopnest = 0;
+}
+
+
+/*
+ * The eval command.
+ */
+
+int
+evalcmd(int argc, char **argv)
+{
+        char *p;
+        char *concat;
+        char **ap;
+
+        if (argc > 1) {
+                p = argv[1];
+                if (argc > 2) {
+                        STARTSTACKSTR(concat);
+                        ap = argv + 2;
+                        for (;;) {
+                                STPUTS(p, concat);
+                                if ((p = *ap++) == NULL)
+                                        break;
+                                STPUTC(' ', concat);
+                        }
+                        STPUTC('\0', concat);
+                        p = grabstackstr(concat);
+                }
+                evalstring(p, builtin_flags);
+        } else
+                exitstatus = 0;
+        return exitstatus;
+}
+
+
+/*
+ * Execute a command or commands contained in a string.
+ */
+
+void
+evalstring(const char *s, int flags)
+{
+	union node *n;
+	struct stackmark smark;
+	int flags_exit;
+	int any;
+
+	flags_exit = flags & EV_EXIT;
+	flags &= ~EV_EXIT;
+	any = 0;
+	setstackmark(&smark);
+	setinputstring(s, 1);
+	while ((n = parsecmd(0)) != NEOF) {
+		if (n != NULL && !nflag) {
+			if (flags_exit && preadateof())
+				evaltree(n, flags | EV_EXIT);
+			else
+				evaltree(n, flags);
+			any = 1;
+			if (evalskip)
+				break;
+		}
+		popstackmark(&smark);
+		setstackmark(&smark);
+	}
+	popfile();
+	popstackmark(&smark);
+	if (!any)
+		exitstatus = 0;
+	if (flags_exit)
+		exraise(EXEXIT);
+}
+
+
+/*
+ * Evaluate a parse tree.  The value is left in the global variable
+ * exitstatus.
+ */
+
+void
+evaltree(union node *n, int flags)
+{
+	int do_etest;
+	union node *next;
+	struct stackmark smark;
+
+	setstackmark(&smark);
+	do_etest = 0;
+	if (n == NULL) {
+		TRACE(("evaltree(NULL) called\n"));
+		exitstatus = 0;
+		goto out;
+	}
+	do {
+		next = NULL;
+#ifndef NO_HISTORY
+		displayhist = 1;	/* show history substitutions done with fc */
+#endif
+		TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
+		switch (n->type) {
+		case NSEMI:
+			evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
+			if (evalskip)
+				goto out;
+			next = n->nbinary.ch2;
+			break;
+		case NAND:
+			evaltree(n->nbinary.ch1, EV_TESTED);
+			if (evalskip || exitstatus != 0) {
+				goto out;
+			}
+			next = n->nbinary.ch2;
+			break;
+		case NOR:
+			evaltree(n->nbinary.ch1, EV_TESTED);
+			if (evalskip || exitstatus == 0)
+				goto out;
+			next = n->nbinary.ch2;
+			break;
+		case NREDIR:
+			evalredir(n, flags);
+			break;
+		case NSUBSHELL:
+			evalsubshell(n, flags);
+			do_etest = !(flags & EV_TESTED);
+			break;
+		case NBACKGND:
+			evalsubshell(n, flags);
+			break;
+		case NIF: {
+			evaltree(n->nif.test, EV_TESTED);
+			if (evalskip)
+				goto out;
+			if (exitstatus == 0)
+				next = n->nif.ifpart;
+			else if (n->nif.elsepart)
+				next = n->nif.elsepart;
+			else
+				exitstatus = 0;
+			break;
+		}
+		case NWHILE:
+		case NUNTIL:
+			evalloop(n, flags & ~EV_EXIT);
+			break;
+		case NFOR:
+			evalfor(n, flags & ~EV_EXIT);
+			break;
+		case NCASE:
+			next = evalcase(n);
+			break;
+		case NCLIST:
+			next = n->nclist.body;
+			break;
+		case NCLISTFALLTHRU:
+			if (n->nclist.body) {
+				evaltree(n->nclist.body, flags & ~EV_EXIT);
+				if (evalskip)
+					goto out;
+			}
+			next = n->nclist.next;
+			break;
+		case NDEFUN:
+			defun(n->narg.text, n->narg.next);
+			exitstatus = 0;
+			break;
+		case NNOT:
+			evaltree(n->nnot.com, EV_TESTED);
+			if (evalskip)
+				goto out;
+			exitstatus = !exitstatus;
+			break;
+
+		case NPIPE:
+			evalpipe(n);
+			do_etest = !(flags & EV_TESTED);
+			break;
+		case NCMD:
+			evalcommand(n, flags, (struct backcmd *)NULL);
+			do_etest = !(flags & EV_TESTED);
+			break;
+		default:
+			out1fmt("Node type = %d\n", n->type);
+			flushout(&output);
+			break;
+		}
+		n = next;
+		popstackmark(&smark);
+		setstackmark(&smark);
+	} while (n != NULL);
+out:
+	popstackmark(&smark);
+	if (pendingsig)
+		dotrap();
+	if (eflag && exitstatus != 0 && do_etest)
+		exitshell(exitstatus);
+	if (flags & EV_EXIT)
+		exraise(EXEXIT);
+}
+
+
+static void
+evalloop(union node *n, int flags)
+{
+	int status;
+
+	loopnest++;
+	status = 0;
+	for (;;) {
+		if (!evalskip)
+			evaltree(n->nbinary.ch1, EV_TESTED);
+		if (evalskip) {
+			if (evalskip == SKIPCONT && --skipcount <= 0) {
+				evalskip = 0;
+				continue;
+			}
+			if (evalskip == SKIPBREAK && --skipcount <= 0)
+				evalskip = 0;
+			if (evalskip == SKIPRETURN)
+				status = exitstatus;
+			break;
+		}
+		if (n->type == NWHILE) {
+			if (exitstatus != 0)
+				break;
+		} else {
+			if (exitstatus == 0)
+				break;
+		}
+		evaltree(n->nbinary.ch2, flags);
+		status = exitstatus;
+	}
+	loopnest--;
+	exitstatus = status;
+}
+
+
+
+static void
+evalfor(union node *n, int flags)
+{
+	struct arglist arglist;
+	union node *argp;
+	int i;
+	int status;
+
+	emptyarglist(&arglist);
+	for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
+		oexitstatus = exitstatus;
+		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
+	}
+
+	loopnest++;
+	status = 0;
+	for (i = 0; i < arglist.count; i++) {
+		setvar(n->nfor.var, arglist.args[i], 0);
+		evaltree(n->nfor.body, flags);
+		status = exitstatus;
+		if (evalskip) {
+			if (evalskip == SKIPCONT && --skipcount <= 0) {
+				evalskip = 0;
+				continue;
+			}
+			if (evalskip == SKIPBREAK && --skipcount <= 0)
+				evalskip = 0;
+			break;
+		}
+	}
+	loopnest--;
+	exitstatus = status;
+}
+
+
+/*
+ * Evaluate a case statement, returning the selected tree.
+ *
+ * The exit status needs care to get right.
+ */
+
+static union node *
+evalcase(union node *n)
+{
+	union node *cp;
+	union node *patp;
+	struct arglist arglist;
+
+	emptyarglist(&arglist);
+	oexitstatus = exitstatus;
+	expandarg(n->ncase.expr, &arglist, EXP_TILDE);
+	for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
+		for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
+			if (casematch(patp, arglist.args[0])) {
+				while (cp->nclist.next &&
+				    cp->type == NCLISTFALLTHRU &&
+				    cp->nclist.body == NULL)
+					cp = cp->nclist.next;
+				if (cp->nclist.next &&
+				    cp->type == NCLISTFALLTHRU)
+					return (cp);
+				if (cp->nclist.body == NULL)
+					exitstatus = 0;
+				return (cp->nclist.body);
+			}
+		}
+	}
+	exitstatus = 0;
+	return (NULL);
+}
+
+
+
+/*
+ * Kick off a subshell to evaluate a tree.
+ */
+
+static void
+evalsubshell(union node *n, int flags)
+{
+	struct job *jp;
+	int backgnd = (n->type == NBACKGND);
+
+	oexitstatus = exitstatus;
+	expredir(n->nredir.redirect);
+	if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
+			forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
+		if (backgnd)
+			flags &=~ EV_TESTED;
+		redirect(n->nredir.redirect, 0);
+		evaltree(n->nredir.n, flags | EV_EXIT);	/* never returns */
+	} else if (! backgnd) {
+		INTOFF;
+		exitstatus = waitforjob(jp, (int *)NULL);
+		INTON;
+	} else
+		exitstatus = 0;
+}
+
+
+/*
+ * Evaluate a redirected compound command.
+ */
+
+static void
+evalredir(union node *n, int flags)
+{
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	volatile int in_redirect = 1;
+
+	oexitstatus = exitstatus;
+	expredir(n->nredir.redirect);
+	savehandler = handler;
+	if (setjmp(jmploc.loc)) {
+		int e;
+
+		handler = savehandler;
+		e = exception;
+		popredir();
+		if (e == EXERROR || e == EXEXEC) {
+			if (in_redirect) {
+				exitstatus = 2;
+				FORCEINTON;
+				return;
+			}
+		}
+		longjmp(handler->loc, 1);
+	} else {
+		INTOFF;
+		handler = &jmploc;
+		redirect(n->nredir.redirect, REDIR_PUSH);
+		in_redirect = 0;
+		INTON;
+		evaltree(n->nredir.n, flags);
+	}
+	INTOFF;
+	handler = savehandler;
+	popredir();
+	INTON;
+}
+
+
+static void
+exphere(union node *redir, struct arglist *fn)
+{
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	struct localvar *savelocalvars;
+	int need_longjmp = 0;
+	unsigned char saveoptreset;
+
+	redir->nhere.expdoc = "";
+	savelocalvars = localvars;
+	localvars = NULL;
+	saveoptreset = shellparam.reset;
+	forcelocal++;
+	savehandler = handler;
+	if (setjmp(jmploc.loc))
+		need_longjmp = exception != EXERROR && exception != EXEXEC;
+	else {
+		handler = &jmploc;
+		expandarg(redir->nhere.doc, fn, 0);
+		redir->nhere.expdoc = fn->args[0];
+		INTOFF;
+	}
+	handler = savehandler;
+	forcelocal--;
+	poplocalvars();
+	localvars = savelocalvars;
+	shellparam.reset = saveoptreset;
+	if (need_longjmp)
+		longjmp(handler->loc, 1);
+	INTON;
+}
+
+
+/*
+ * Compute the names of the files in a redirection list.
+ */
+
+static void
+expredir(union node *n)
+{
+	union node *redir;
+
+	for (redir = n ; redir ; redir = redir->nfile.next) {
+		struct arglist fn;
+		emptyarglist(&fn);
+		switch (redir->type) {
+		case NFROM:
+		case NTO:
+		case NFROMTO:
+		case NAPPEND:
+		case NCLOBBER:
+			expandarg(redir->nfile.fname, &fn, EXP_TILDE);
+			redir->nfile.expfname = fn.args[0];
+			break;
+		case NFROMFD:
+		case NTOFD:
+			if (redir->ndup.vname) {
+				expandarg(redir->ndup.vname, &fn, EXP_TILDE);
+				fixredir(redir, fn.args[0], 1);
+			}
+			break;
+		case NXHERE:
+			exphere(redir, &fn);
+			break;
+		}
+	}
+}
+
+
+
+/*
+ * Evaluate a pipeline.  All the processes in the pipeline are children
+ * of the process creating the pipeline.  (This differs from some versions
+ * of the shell, which make the last process in a pipeline the parent
+ * of all the rest.)
+ */
+
+static void
+evalpipe(union node *n)
+{
+	struct job *jp;
+	struct nodelist *lp;
+	int pipelen;
+	int prevfd;
+	int pip[2];
+
+	TRACE(("evalpipe(%p) called\n", (void *)n));
+	pipelen = 0;
+	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
+		pipelen++;
+	INTOFF;
+	jp = makejob(n, pipelen);
+	prevfd = -1;
+	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
+		prehash(lp->n);
+		pip[1] = -1;
+		if (lp->next) {
+			if (pipe(pip) < 0) {
+				if (prevfd >= 0)
+					close(prevfd);
+				error("Pipe call failed: %s", strerror(errno));
+			}
+		}
+		if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
+			INTON;
+			if (prevfd > 0) {
+				dup2(prevfd, 0);
+				close(prevfd);
+			}
+			if (pip[1] >= 0) {
+				if (!(prevfd >= 0 && pip[0] == 0))
+					close(pip[0]);
+				if (pip[1] != 1) {
+					dup2(pip[1], 1);
+					close(pip[1]);
+				}
+			}
+			evaltree(lp->n, EV_EXIT);
+		}
+		if (prevfd >= 0)
+			close(prevfd);
+		prevfd = pip[0];
+		if (pip[1] != -1)
+			close(pip[1]);
+	}
+	INTON;
+	if (n->npipe.backgnd == 0) {
+		INTOFF;
+		exitstatus = waitforjob(jp, (int *)NULL);
+		TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
+		INTON;
+	} else
+		exitstatus = 0;
+}
+
+
+
+static int
+is_valid_fast_cmdsubst(union node *n)
+{
+
+	return (n->type == NCMD);
+}
+
+/*
+ * Execute a command inside back quotes.  If it's a builtin command, we
+ * want to save its output in a block obtained from malloc.  Otherwise
+ * we fork off a subprocess and get the output of the command via a pipe.
+ * Should be called with interrupts off.
+ */
+
+void
+evalbackcmd(union node *n, struct backcmd *result)
+{
+	int pip[2];
+	struct job *jp;
+	struct stackmark smark;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	struct localvar *savelocalvars;
+	unsigned char saveoptreset;
+
+	result->fd = -1;
+	result->buf = NULL;
+	result->nleft = 0;
+	result->jp = NULL;
+	if (n == NULL) {
+		exitstatus = 0;
+		return;
+	}
+	setstackmark(&smark);
+	exitstatus = oexitstatus;
+	if (is_valid_fast_cmdsubst(n)) {
+		savelocalvars = localvars;
+		localvars = NULL;
+		saveoptreset = shellparam.reset;
+		forcelocal++;
+		savehandler = handler;
+		if (setjmp(jmploc.loc)) {
+			if (exception == EXERROR || exception == EXEXEC)
+				exitstatus = 2;
+			else if (exception != 0) {
+				handler = savehandler;
+				forcelocal--;
+				poplocalvars();
+				localvars = savelocalvars;
+				shellparam.reset = saveoptreset;
+				longjmp(handler->loc, 1);
+			}
+		} else {
+			handler = &jmploc;
+			evalcommand(n, EV_BACKCMD, result);
+		}
+		handler = savehandler;
+		forcelocal--;
+		poplocalvars();
+		localvars = savelocalvars;
+		shellparam.reset = saveoptreset;
+	} else {
+		if (pipe(pip) < 0)
+			error("Pipe call failed: %s", strerror(errno));
+		jp = makejob(n, 1);
+		if (forkshell(jp, n, FORK_NOJOB) == 0) {
+			FORCEINTON;
+			close(pip[0]);
+			if (pip[1] != 1) {
+				dup2(pip[1], 1);
+				close(pip[1]);
+			}
+			evaltree(n, EV_EXIT);
+		}
+		close(pip[1]);
+		result->fd = pip[0];
+		result->jp = jp;
+	}
+	popstackmark(&smark);
+	TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
+		result->fd, result->buf, result->nleft, result->jp));
+}
+
+static int
+mustexpandto(const char *argtext, const char *mask)
+{
+	for (;;) {
+		if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
+			argtext++;
+			continue;
+		}
+		if (*argtext == CTLESC)
+			argtext++;
+		else if (BASESYNTAX[(int)*argtext] == CCTL)
+			return (0);
+		if (*argtext != *mask)
+			return (0);
+		if (*argtext == '\0')
+			return (1);
+		argtext++;
+		mask++;
+	}
+}
+
+static int
+isdeclarationcmd(struct narg *arg)
+{
+	int have_command = 0;
+
+	if (arg == NULL)
+		return (0);
+	while (mustexpandto(arg->text, "command")) {
+		have_command = 1;
+		arg = &arg->next->narg;
+		if (arg == NULL)
+			return (0);
+		/*
+		 * To also allow "command -p" and "command --" as part of
+		 * a declaration command, add code here.
+		 * We do not do this, as ksh does not do it either and it
+		 * is not required by POSIX.
+		 */
+	}
+	return (mustexpandto(arg->text, "export") ||
+	    mustexpandto(arg->text, "readonly") ||
+	    (mustexpandto(arg->text, "local") &&
+		(have_command || !isfunc("local"))));
+}
+
+static void
+xtracecommand(struct arglist *varlist, int argc, char **argv)
+{
+	char sep = 0;
+	const char *text, *p, *ps4;
+	int i;
+
+	ps4 = expandstr(ps4val());
+	out2str(ps4 != NULL ? ps4 : ps4val());
+	for (i = 0; i < varlist->count; i++) {
+		text = varlist->args[i];
+		if (sep != 0)
+			out2c(' ');
+		p = strchr(text, '=');
+		if (p != NULL) {
+			p++;
+			outbin(text, p - text, out2);
+			out2qstr(p);
+		} else
+			out2qstr(text);
+		sep = ' ';
+	}
+	for (i = 0; i < argc; i++) {
+		text = argv[i];
+		if (sep != 0)
+			out2c(' ');
+		out2qstr(text);
+		sep = ' ';
+	}
+	out2c('\n');
+	flushout(&errout);
+}
+
+/*
+ * Check if a builtin can safely be executed in the same process,
+ * even though it should be in a subshell (command substitution).
+ * Note that jobid, jobs, times and trap can show information not
+ * available in a child process; this is deliberate.
+ * The arguments should already have been expanded.
+ */
+static int
+safe_builtin(int idx, int argc, char **argv)
+{
+	/* Generated from builtins.def. */
+	if (safe_builtin_always(idx))
+		return (1);
+	if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
+	    idx == UMASKCMD)
+		return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
+	if (idx == SETCMD)
+		return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
+		    argv[1][0] == '+') && argv[1][1] == 'o' &&
+		    argv[1][2] == '\0'));
+	return (0);
+}
+
+/*
+ * Execute a simple command.
+ * Note: This may or may not return if (flags & EV_EXIT).
+ */
+
+static void
+evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
+{
+	union node *argp;
+	struct arglist arglist;
+	struct arglist varlist;
+	char **argv;
+	int argc;
+	char **envp;
+	int varflag;
+	int mode;
+	int pip[2];
+	struct cmdentry cmdentry;
+	struct job *jp;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	char *savecmdname;
+	struct shparam saveparam;
+	struct localvar *savelocalvars;
+	struct parsefile *savetopfile;
+	volatile int e;
+	char *lastarg;
+	int signaled;
+	int do_clearcmdentry;
+	const char *path = pathval();
+	int i;
+
+	/* First expand the arguments. */
+	TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
+	emptyarglist(&arglist);
+	emptyarglist(&varlist);
+	varflag = 1;
+	jp = NULL;
+	do_clearcmdentry = 0;
+	oexitstatus = exitstatus;
+	exitstatus = 0;
+	/* Add one slot at the beginning for tryexec(). */
+	appendarglist(&arglist, nullstr);
+	for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
+		if (varflag && isassignment(argp->narg.text)) {
+			expandarg(argp, varflag == 1 ? &varlist : &arglist,
+			    EXP_VARTILDE);
+			continue;
+		} else if (varflag == 1)
+			varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
+		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
+	}
+	appendarglist(&arglist, nullstr);
+	expredir(cmd->ncmd.redirect);
+	argc = arglist.count - 2;
+	argv = &arglist.args[1];
+
+	argv[argc] = NULL;
+	lastarg = NULL;
+	if (iflag && funcnest == 0 && argc > 0)
+		lastarg = argv[argc - 1];
+
+	/* Print the command if xflag is set. */
+	if (xflag)
+		xtracecommand(&varlist, argc, argv);
+
+	/* Now locate the command. */
+	if (argc == 0) {
+		/* Variable assignment(s) without command */
+		cmdentry.cmdtype = CMDBUILTIN;
+		cmdentry.u.index = BLTINCMD;
+		cmdentry.special = 0;
+	} else {
+		static const char PATH[] = "PATH=";
+		int cmd_flags = 0, bltinonly = 0;
+
+		/*
+		 * Modify the command lookup path, if a PATH= assignment
+		 * is present
+		 */
+		for (i = 0; i < varlist.count; i++)
+			if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) {
+				path = varlist.args[i] + sizeof(PATH) - 1;
+				/*
+				 * On `PATH=... command`, we need to make
+				 * sure that the command isn't using the
+				 * non-updated hash table of the outer PATH
+				 * setting and we need to make sure that
+				 * the hash table isn't filled with items
+				 * from the temporary setting.
+				 *
+				 * It would be better to forbit using and
+				 * updating the table while this command
+				 * runs, by the command finding mechanism
+				 * is heavily integrated with hash handling,
+				 * so we just delete the hash before and after
+				 * the command runs. Partly deleting like
+				 * changepatch() does doesn't seem worth the
+				 * bookinging effort, since most such runs add
+				 * directories in front of the new PATH.
+				 */
+				clearcmdentry();
+				do_clearcmdentry = 1;
+			}
+
+		for (;;) {
+			if (bltinonly) {
+				cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
+				if (cmdentry.u.index < 0) {
+					cmdentry.u.index = BLTINCMD;
+					argv--;
+					argc++;
+					break;
+				}
+			} else
+				find_command(argv[0], &cmdentry, cmd_flags, path);
+			/* implement the bltin and command builtins here */
+			if (cmdentry.cmdtype != CMDBUILTIN)
+				break;
+			if (cmdentry.u.index == BLTINCMD) {
+				if (argc == 1)
+					break;
+				argv++;
+				argc--;
+				bltinonly = 1;
+			} else if (cmdentry.u.index == COMMANDCMD) {
+				if (argc == 1)
+					break;
+				if (!strcmp(argv[1], "-p")) {
+					if (argc == 2)
+						break;
+					if (argv[2][0] == '-') {
+						if (strcmp(argv[2], "--"))
+							break;
+						if (argc == 3)
+							break;
+						argv += 3;
+						argc -= 3;
+					} else {
+						argv += 2;
+						argc -= 2;
+					}
+					path = _PATH_STDPATH;
+					clearcmdentry();
+					do_clearcmdentry = 1;
+				} else if (!strcmp(argv[1], "--")) {
+					if (argc == 2)
+						break;
+					argv += 2;
+					argc -= 2;
+				} else if (argv[1][0] == '-')
+					break;
+				else {
+					argv++;
+					argc--;
+				}
+				cmd_flags |= DO_NOFUNC;
+				bltinonly = 0;
+			} else
+				break;
+		}
+		/*
+		 * Special builtins lose their special properties when
+		 * called via 'command'.
+		 */
+		if (cmd_flags & DO_NOFUNC)
+			cmdentry.special = 0;
+	}
+
+	/* Fork off a child process if necessary. */
+	if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
+	    && ((flags & EV_EXIT) == 0 || have_traps()))
+	 || ((flags & EV_BACKCMD) != 0
+	    && (cmdentry.cmdtype != CMDBUILTIN ||
+		 !safe_builtin(cmdentry.u.index, argc, argv)))) {
+		jp = makejob(cmd, 1);
+		mode = FORK_FG;
+		if (flags & EV_BACKCMD) {
+			mode = FORK_NOJOB;
+			if (pipe(pip) < 0)
+				error("Pipe call failed: %s", strerror(errno));
+		}
+		if (cmdentry.cmdtype == CMDNORMAL &&
+		    cmd->ncmd.redirect == NULL &&
+		    varlist.count == 0 &&
+		    (mode == FORK_FG || mode == FORK_NOJOB) &&
+		    !disvforkset() && !iflag && !mflag) {
+			vforkexecshell(jp, argv, environment(), path,
+			    cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
+			goto parent;
+		}
+		if (forkshell(jp, cmd, mode) != 0)
+			goto parent;	/* at end of routine */
+		if (flags & EV_BACKCMD) {
+			FORCEINTON;
+			close(pip[0]);
+			if (pip[1] != 1) {
+				dup2(pip[1], 1);
+				close(pip[1]);
+			}
+			flags &= ~EV_BACKCMD;
+		}
+		flags |= EV_EXIT;
+	}
+
+	/* This is the child process if a fork occurred. */
+	/* Execute the command. */
+	if (cmdentry.cmdtype == CMDFUNCTION) {
+#ifdef DEBUG
+		trputs("Shell function:  ");  trargs(argv);
+#endif
+		saveparam = shellparam;
+		shellparam.malloc = 0;
+		shellparam.reset = 1;
+		shellparam.nparam = argc - 1;
+		shellparam.p = argv + 1;
+		shellparam.optp = NULL;
+		shellparam.optnext = NULL;
+		INTOFF;
+		savelocalvars = localvars;
+		localvars = NULL;
+		reffunc(cmdentry.u.func);
+		savehandler = handler;
+		if (setjmp(jmploc.loc)) {
+			popredir();
+			unreffunc(cmdentry.u.func);
+			poplocalvars();
+			localvars = savelocalvars;
+			freeparam(&shellparam);
+			shellparam = saveparam;
+			funcnest--;
+			handler = savehandler;
+			longjmp(handler->loc, 1);
+		}
+		handler = &jmploc;
+		funcnest++;
+		redirect(cmd->ncmd.redirect, REDIR_PUSH);
+		INTON;
+		for (i = 0; i < varlist.count; i++)
+			mklocal(varlist.args[i]);
+		exitstatus = oexitstatus;
+		evaltree(getfuncnode(cmdentry.u.func),
+		    flags & (EV_TESTED | EV_EXIT));
+		INTOFF;
+		unreffunc(cmdentry.u.func);
+		poplocalvars();
+		localvars = savelocalvars;
+		freeparam(&shellparam);
+		shellparam = saveparam;
+		handler = savehandler;
+		funcnest--;
+		popredir();
+		INTON;
+		if (evalskip == SKIPRETURN) {
+			evalskip = 0;
+			skipcount = 0;
+		}
+		if (jp)
+			exitshell(exitstatus);
+	} else if (cmdentry.cmdtype == CMDBUILTIN) {
+#ifdef DEBUG
+		trputs("builtin command:  ");  trargs(argv);
+#endif
+		mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
+		if (flags == EV_BACKCMD) {
+			memout.nextc = memout.buf;
+			mode |= REDIR_BACKQ;
+		}
+		savecmdname = commandname;
+		savetopfile = getcurrentfile();
+		cmdenviron = &varlist;
+		e = -1;
+		savehandler = handler;
+		if (setjmp(jmploc.loc)) {
+			e = exception;
+			if (e == EXINT)
+				exitstatus = SIGINT+128;
+			else if (e != EXEXIT)
+				exitstatus = 2;
+			goto cmddone;
+		}
+		handler = &jmploc;
+		redirect(cmd->ncmd.redirect, mode);
+		outclearerror(out1);
+		/*
+		 * If there is no command word, redirection errors should
+		 * not be fatal but assignment errors should.
+		 */
+		if (argc == 0)
+			cmdentry.special = 1;
+		listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
+		if (argc > 0)
+			bltinsetlocale();
+		commandname = argv[0];
+		argptr = argv + 1;
+		nextopt_optptr = NULL;		/* initialize nextopt */
+		builtin_flags = flags;
+		exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
+		flushall();
+		if (outiserror(out1)) {
+			warning("write error on stdout");
+			if (exitstatus == 0 || exitstatus == 1)
+				exitstatus = 2;
+		}
+cmddone:
+		if (argc > 0)
+			bltinunsetlocale();
+		cmdenviron = NULL;
+		out1 = &output;
+		out2 = &errout;
+		freestdout();
+		handler = savehandler;
+		commandname = savecmdname;
+		if (jp)
+			exitshell(exitstatus);
+		if (flags == EV_BACKCMD) {
+			backcmd->buf = memout.buf;
+			backcmd->nleft = memout.buf != NULL ?
+			    memout.nextc - memout.buf : 0;
+			memout.buf = NULL;
+			memout.nextc = NULL;
+			memout.bufend = NULL;
+			memout.bufsize = 64;
+		}
+		if (cmdentry.u.index != EXECCMD)
+			popredir();
+		if (e != -1) {
+			if ((e != EXERROR && e != EXEXEC)
+			    || cmdentry.special)
+				exraise(e);
+			popfilesupto(savetopfile);
+			if (flags != EV_BACKCMD)
+				FORCEINTON;
+		}
+	} else {
+#ifdef DEBUG
+		trputs("normal command:  ");  trargs(argv);
+#endif
+		redirect(cmd->ncmd.redirect, 0);
+		for (i = 0; i < varlist.count; i++)
+			setvareq(varlist.args[i], VEXPORT|VSTACK);
+		envp = environment();
+		shellexec(argv, envp, path, cmdentry.u.index);
+		/*NOTREACHED*/
+	}
+	goto out;
+
+parent:	/* parent process gets here (if we forked) */
+	if (mode == FORK_FG) {	/* argument to fork */
+		INTOFF;
+		exitstatus = waitforjob(jp, &signaled);
+		INTON;
+		if (iflag && loopnest > 0 && signaled) {
+			evalskip = SKIPBREAK;
+			skipcount = loopnest;
+		}
+	} else if (mode == FORK_NOJOB) {
+		backcmd->fd = pip[0];
+		close(pip[1]);
+		backcmd->jp = jp;
+	}
+
+out:
+	if (lastarg)
+		setvar("_", lastarg, 0);
+	if (do_clearcmdentry)
+		clearcmdentry();
+}
+
+
+
+/*
+ * Search for a command.  This is called before we fork so that the
+ * location of the command will be available in the parent as well as
+ * the child.  The check for "goodname" is an overly conservative
+ * check that the name will not be subject to expansion.
+ */
+
+static void
+prehash(union node *n)
+{
+	struct cmdentry entry;
+
+	if (n && n->type == NCMD && n->ncmd.args)
+		if (goodname(n->ncmd.args->narg.text))
+			find_command(n->ncmd.args->narg.text, &entry, 0,
+				     pathval());
+}
+
+
+
+/*
+ * Builtin commands.  Builtin commands whose functions are closely
+ * tied to evaluation are implemented here.
+ */
+
+/*
+ * No command given, a bltin command with no arguments, or a bltin command
+ * with an invalid name.
+ */
+
+int
+bltincmd(int argc, char **argv)
+{
+	if (argc > 1) {
+		out2fmt_flush("%s: not found\n", argv[1]);
+		return 127;
+	}
+	/*
+	 * Preserve exitstatus of a previous possible command substitution
+	 * as POSIX mandates
+	 */
+	return exitstatus;
+}
+
+
+/*
+ * Handle break and continue commands.  Break, continue, and return are
+ * all handled by setting the evalskip flag.  The evaluation routines
+ * above all check this flag, and if it is set they start skipping
+ * commands rather than executing them.  The variable skipcount is
+ * the number of loops to break/continue, or the number of function
+ * levels to return.  (The latter is always 1.)  It should probably
+ * be an error to break out of more loops than exist, but it isn't
+ * in the standard shell so we don't make it one here.
+ */
+
+int
+breakcmd(int argc, char **argv)
+{
+	long n;
+	char *end;
+
+	if (argc > 1) {
+		/* Allow arbitrarily large numbers. */
+		n = strtol(argv[1], &end, 10);
+		if (!is_digit(argv[1][0]) || *end != '\0')
+			error("Illegal number: %s", argv[1]);
+	} else
+		n = 1;
+	if (n > loopnest)
+		n = loopnest;
+	if (n > 0) {
+		evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
+		skipcount = n;
+	}
+	return 0;
+}
+
+/*
+ * The `command' command.
+ */
+int
+commandcmd(int argc __unused, char **argv __unused)
+{
+	const char *path;
+	int ch;
+	int cmd = -1;
+
+	path = bltinlookup("PATH", 1);
+
+	while ((ch = nextopt("pvV")) != '\0') {
+		switch (ch) {
+		case 'p':
+			path = _PATH_STDPATH;
+			break;
+		case 'v':
+			cmd = TYPECMD_SMALLV;
+			break;
+		case 'V':
+			cmd = TYPECMD_BIGV;
+			break;
+		}
+	}
+
+	if (cmd != -1) {
+		if (*argptr == NULL || argptr[1] != NULL)
+			error("wrong number of arguments");
+		return typecmd_impl(2, argptr - 1, cmd, path);
+	}
+	if (*argptr != NULL)
+		error("commandcmd bad call");
+
+	/*
+	 * Do nothing successfully if no command was specified;
+	 * ksh also does this.
+	 */
+	return 0;
+}
+
+
+/*
+ * The return command.
+ */
+
+int
+returncmd(int argc, char **argv)
+{
+	int ret = argc > 1 ? number(argv[1]) : oexitstatus;
+
+	evalskip = SKIPRETURN;
+	skipcount = 1;
+	return ret;
+}
+
+
+int
+falsecmd(int argc __unused, char **argv __unused)
+{
+	return 1;
+}
+
+
+int
+truecmd(int argc __unused, char **argv __unused)
+{
+	return 0;
+}
+
+
+int
+execcmd(int argc, char **argv)
+{
+	int i;
+
+	/*
+	 * Because we have historically not supported any options,
+	 * only treat "--" specially.
+	 */
+	if (argc > 1 && strcmp(argv[1], "--") == 0)
+		argc--, argv++;
+	if (argc > 1) {
+		iflag = 0;		/* exit on error */
+		mflag = 0;
+		optschanged();
+		for (i = 0; i < cmdenviron->count; i++)
+			setvareq(cmdenviron->args[i], VEXPORT|VSTACK);
+		shellexec(argv + 1, environment(), pathval(), 0);
+
+	}
+	return 0;
+}
+
+
+int
+timescmd(int argc __unused, char **argv __unused)
+{
+	struct rusage ru;
+	long shumins, shsmins, chumins, chsmins;
+	double shusecs, shssecs, chusecs, chssecs;
+
+	if (getrusage(RUSAGE_SELF, &ru) < 0)
+		return 1;
+	shumins = ru.ru_utime.tv_sec / 60;
+	shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
+	shsmins = ru.ru_stime.tv_sec / 60;
+	shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
+	if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
+		return 1;
+	chumins = ru.ru_utime.tv_sec / 60;
+	chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
+	chsmins = ru.ru_stime.tv_sec / 60;
+	chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
+	out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
+	    shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
+	return 0;
+}
diff --git a/bin/1sh/eval.h b/bin/1sh/eval.h
new file mode 100644
index 00000000..d413ccd5
--- /dev/null
+++ b/bin/1sh/eval.h
@@ -0,0 +1,70 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)eval.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/eval.h 314436 2017-02-28 23:42:47Z imp $
+ */
+
+extern char *commandname;	/* currently executing command */
+extern int exitstatus;		/* exit status of last command */
+extern int oexitstatus;		/* saved exit status */
+extern struct arglist *cmdenviron;  /* environment for builtin command */
+
+
+struct backcmd {		/* result of evalbackcmd */
+	int fd;			/* file descriptor to read from */
+	char *buf;		/* buffer */
+	int nleft;		/* number of chars in buffer */
+	struct job *jp;		/* job structure for command */
+};
+
+void reseteval(void);
+
+/* flags in argument to evaltree/evalstring */
+#define EV_EXIT 01		/* exit after evaluating tree */
+#define EV_TESTED 02		/* exit status is checked; ignore -e flag */
+#define EV_BACKCMD 04		/* command executing within back quotes */
+
+void evalstring(const char *, int);
+union node;	/* BLETCH for ansi C */
+void evaltree(union node *, int);
+void evalbackcmd(union node *, struct backcmd *);
+
+/* in_function returns nonzero if we are currently evaluating a function */
+#define in_function()	funcnest
+extern int funcnest;
+extern int evalskip;
+extern int skipcount;
+
+/* reasons for skipping commands (see comment on breakcmd routine) */
+#define SKIPBREAK	1
+#define SKIPCONT	2
+#define SKIPRETURN	3
diff --git a/bin/1sh/exec.c b/bin/1sh/exec.c
new file mode 100644
index 00000000..81efa565
--- /dev/null
+++ b/bin/1sh/exec.c
@@ -0,0 +1,784 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)exec.c	8.4 (Berkeley) 6/8/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/exec.c 336320 2018-07-15 21:55:17Z jilles $ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <paths.h>
+#include <stdlib.h>
+
+/*
+ * When commands are first encountered, they are entered in a hash table.
+ * This ensures that a full path search will not have to be done for them
+ * on each invocation.
+ *
+ * We should investigate converting to a linear search, even though that
+ * would make the command name "hash" a misnomer.
+ */
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"
+#include "parser.h"
+#include "redir.h"
+#include "eval.h"
+#include "exec.h"
+#include "builtins.h"
+#include "var.h"
+#include "options.h"
+#include "input.h"
+#include "output.h"
+#include "syntax.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "show.h"
+#include "jobs.h"
+#include "alias.h"
+
+
+#define CMDTABLESIZE 31		/* should be prime */
+
+
+
+struct tblentry {
+	struct tblentry *next;	/* next entry in hash chain */
+	union param param;	/* definition of builtin function */
+	int special;		/* flag for special builtin commands */
+	signed char cmdtype;	/* index identifying command */
+	char cmdname[];		/* name of command */
+};
+
+
+static struct tblentry *cmdtable[CMDTABLESIZE];
+static int cmdtable_cd = 0;	/* cmdtable contains cd-dependent entries */
+int exerrno = 0;			/* Last exec error */
+
+
+static void tryexec(char *, char **, char **);
+static void printentry(struct tblentry *, int);
+static struct tblentry *cmdlookup(const char *, int);
+static void delete_cmd_entry(void);
+static void addcmdentry(const char *, struct cmdentry *);
+
+
+
+/*
+ * Exec a program.  Never returns.  If you change this routine, you may
+ * have to change the find_command routine as well.
+ *
+ * The argv array may be changed and element argv[-1] should be writable.
+ */
+
+void
+shellexec(char **argv, char **envp, const char *path, int idx)
+{
+	char *cmdname;
+	const char *opt;
+	int e;
+
+	if (strchr(argv[0], '/') != NULL) {
+		tryexec(argv[0], argv, envp);
+		e = errno;
+	} else {
+		e = ENOENT;
+		while ((cmdname = padvance(&path, &opt, argv[0])) != NULL) {
+			if (--idx < 0 && opt == NULL) {
+				tryexec(cmdname, argv, envp);
+				if (errno != ENOENT && errno != ENOTDIR)
+					e = errno;
+				if (e == ENOEXEC)
+					break;
+			}
+			stunalloc(cmdname);
+		}
+	}
+
+	/* Map to POSIX errors */
+	if (e == ENOENT || e == ENOTDIR) {
+		exerrno = 127;
+		exerror(EXEXEC, "%s: not found", argv[0]);
+	} else {
+		exerrno = 126;
+		exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
+	}
+}
+
+
+static void
+tryexec(char *cmd, char **argv, char **envp)
+{
+	int e, in;
+	ssize_t n;
+	char buf[256];
+
+	execve(cmd, argv, envp);
+	e = errno;
+	if (e == ENOEXEC) {
+		INTOFF;
+		in = open(cmd, O_RDONLY | O_NONBLOCK);
+		if (in != -1) {
+			n = pread(in, buf, sizeof buf, 0);
+			close(in);
+			if (n > 0 && memchr(buf, '\0', n) != NULL) {
+				errno = ENOEXEC;
+				return;
+			}
+		}
+		*argv = cmd;
+		*--argv = (char *)(_PATH_BSHELL);
+		execve(_PATH_BSHELL, argv, envp);
+	}
+	errno = e;
+}
+
+/*
+ * Do a path search.  The variable path (passed by reference) should be
+ * set to the start of the path before the first call; padvance will update
+ * this value as it proceeds.  Successive calls to padvance will return
+ * the possible path expansions in sequence.  If popt is not NULL, options
+ * are processed: if an option (indicated by a percent sign) appears in
+ * the path entry then *popt will be set to point to it; else *popt will be
+ * set to NULL.  If popt is NULL, percent signs are not special.
+ */
+
+char *
+padvance(const char **path, const char **popt, const char *name)
+{
+	const char *p, *start;
+	char *q;
+	size_t len, namelen;
+
+	if (*path == NULL)
+		return NULL;
+	start = *path;
+	if (popt != NULL)
+		for (p = start; *p && *p != ':' && *p != '%'; p++)
+			; /* nothing */
+	else
+		for (p = start; *p && *p != ':'; p++)
+			; /* nothing */
+	namelen = strlen(name);
+	len = p - start + namelen + 2;	/* "2" is for '/' and '\0' */
+	STARTSTACKSTR(q);
+	CHECKSTRSPACE(len, q);
+	if (p != start) {
+		memcpy(q, start, p - start);
+		q += p - start;
+		*q++ = '/';
+	}
+	memcpy(q, name, namelen + 1);
+	if (popt != NULL) {
+		if (*p == '%') {
+			*popt = ++p;
+			while (*p && *p != ':')  p++;
+		} else
+			*popt = NULL;
+	}
+	if (*p == ':')
+		*path = p + 1;
+	else
+		*path = NULL;
+	return stalloc(len);
+}
+
+
+
+/*** Command hashing code ***/
+
+
+int
+hashcmd(int argc __unused, char **argv __unused)
+{
+	struct tblentry **pp;
+	struct tblentry *cmdp;
+	int c;
+	int verbose;
+	struct cmdentry entry;
+	char *name;
+	int errors;
+
+	errors = 0;
+	verbose = 0;
+	while ((c = nextopt("rv")) != '\0') {
+		if (c == 'r') {
+			clearcmdentry();
+		} else if (c == 'v') {
+			verbose++;
+		}
+	}
+	if (*argptr == NULL) {
+		for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
+			for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
+				if (cmdp->cmdtype == CMDNORMAL)
+					printentry(cmdp, verbose);
+			}
+		}
+		return 0;
+	}
+	while ((name = *argptr) != NULL) {
+		if ((cmdp = cmdlookup(name, 0)) != NULL
+		 && cmdp->cmdtype == CMDNORMAL)
+			delete_cmd_entry();
+		find_command(name, &entry, DO_ERR, pathval());
+		if (entry.cmdtype == CMDUNKNOWN)
+			errors = 1;
+		else if (verbose) {
+			cmdp = cmdlookup(name, 0);
+			if (cmdp != NULL)
+				printentry(cmdp, verbose);
+			else {
+				outfmt(out2, "%s: not found\n", name);
+				errors = 1;
+			}
+			flushall();
+		}
+		argptr++;
+	}
+	return errors;
+}
+
+
+static void
+printentry(struct tblentry *cmdp, int verbose)
+{
+	int idx;
+	const char *path, *opt;
+	char *name;
+
+	if (cmdp->cmdtype == CMDNORMAL) {
+		idx = cmdp->param.index;
+		path = pathval();
+		do {
+			name = padvance(&path, &opt, cmdp->cmdname);
+			stunalloc(name);
+		} while (--idx >= 0);
+		out1str(name);
+	} else if (cmdp->cmdtype == CMDBUILTIN) {
+		out1fmt("builtin %s", cmdp->cmdname);
+	} else if (cmdp->cmdtype == CMDFUNCTION) {
+		out1fmt("function %s", cmdp->cmdname);
+		if (verbose) {
+			INTOFF;
+			name = commandtext(getfuncnode(cmdp->param.func));
+			out1c(' ');
+			out1str(name);
+			ckfree(name);
+			INTON;
+		}
+#ifdef DEBUG
+	} else {
+		error("internal error: cmdtype %d", cmdp->cmdtype);
+#endif
+	}
+	out1c('\n');
+}
+
+
+
+/*
+ * Resolve a command name.  If you change this routine, you may have to
+ * change the shellexec routine as well.
+ */
+
+void
+find_command(const char *name, struct cmdentry *entry, int act,
+    const char *path)
+{
+	struct tblentry *cmdp, loc_cmd;
+	int idx;
+	const char *opt;
+	char *fullname;
+	struct stat statb;
+	int e;
+	int i;
+	int spec;
+	int cd;
+
+	/* If name contains a slash, don't use the hash table */
+	if (strchr(name, '/') != NULL) {
+		entry->cmdtype = CMDNORMAL;
+		entry->u.index = 0;
+		entry->special = 0;
+		return;
+	}
+
+	cd = 0;
+
+	/* If name is in the table, we're done */
+	if ((cmdp = cmdlookup(name, 0)) != NULL) {
+		if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
+			cmdp = NULL;
+		else
+			goto success;
+	}
+
+	/* Check for builtin next */
+	if ((i = find_builtin(name, &spec)) >= 0) {
+		INTOFF;
+		cmdp = cmdlookup(name, 1);
+		if (cmdp->cmdtype == CMDFUNCTION)
+			cmdp = &loc_cmd;
+		cmdp->cmdtype = CMDBUILTIN;
+		cmdp->param.index = i;
+		cmdp->special = spec;
+		INTON;
+		goto success;
+	}
+
+	/* We have to search path. */
+
+	e = ENOENT;
+	idx = -1;
+	for (;(fullname = padvance(&path, &opt, name)) != NULL;
+	    stunalloc(fullname)) {
+		idx++;
+		if (opt) {
+			if (strncmp(opt, "func", 4) == 0) {
+				/* handled below */
+			} else {
+				continue; /* ignore unimplemented options */
+			}
+		}
+		if (fullname[0] != '/')
+			cd = 1;
+		if (stat(fullname, &statb) < 0) {
+			if (errno != ENOENT && errno != ENOTDIR)
+				e = errno;
+			continue;
+		}
+		e = EACCES;	/* if we fail, this will be the error */
+		if (!S_ISREG(statb.st_mode))
+			continue;
+		if (opt) {		/* this is a %func directory */
+			readcmdfile(fullname);
+			if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
+				error("%s not defined in %s", name, fullname);
+			stunalloc(fullname);
+			goto success;
+		}
+#ifdef notdef
+		if (statb.st_uid == geteuid()) {
+			if ((statb.st_mode & 0100) == 0)
+				goto loop;
+		} else if (statb.st_gid == getegid()) {
+			if ((statb.st_mode & 010) == 0)
+				goto loop;
+		} else {
+			if ((statb.st_mode & 01) == 0)
+				goto loop;
+		}
+#endif
+		TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
+		INTOFF;
+		stunalloc(fullname);
+		cmdp = cmdlookup(name, 1);
+		if (cmdp->cmdtype == CMDFUNCTION)
+			cmdp = &loc_cmd;
+		cmdp->cmdtype = CMDNORMAL;
+		cmdp->param.index = idx;
+		cmdp->special = 0;
+		INTON;
+		goto success;
+	}
+
+	if (act & DO_ERR) {
+		if (e == ENOENT || e == ENOTDIR)
+			outfmt(out2, "%s: not found\n", name);
+		else
+			outfmt(out2, "%s: %s\n", name, strerror(e));
+	}
+	entry->cmdtype = CMDUNKNOWN;
+	entry->u.index = 0;
+	entry->special = 0;
+	return;
+
+success:
+	if (cd)
+		cmdtable_cd = 1;
+	entry->cmdtype = cmdp->cmdtype;
+	entry->u = cmdp->param;
+	entry->special = cmdp->special;
+}
+
+
+
+/*
+ * Search the table of builtin commands.
+ */
+
+int
+find_builtin(const char *name, int *special)
+{
+	const unsigned char *bp;
+	size_t len;
+
+	len = strlen(name);
+	for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) {
+		if (bp[0] == len && memcmp(bp + 2, name, len) == 0) {
+			*special = (bp[1] & BUILTIN_SPECIAL) != 0;
+			return bp[1] & ~BUILTIN_SPECIAL;
+		}
+	}
+	return -1;
+}
+
+
+
+/*
+ * Called when a cd is done.  If any entry in cmdtable depends on the current
+ * directory, simply clear cmdtable completely.
+ */
+
+void
+hashcd(void)
+{
+	if (cmdtable_cd)
+		clearcmdentry();
+}
+
+
+
+/*
+ * Called before PATH is changed.  The argument is the new value of PATH;
+ * pathval() still returns the old value at this point.  Called with
+ * interrupts off.
+ */
+
+void
+changepath(const char *newval __unused)
+{
+	clearcmdentry();
+}
+
+
+/*
+ * Clear out cached utility locations.
+ */
+
+void
+clearcmdentry(void)
+{
+	struct tblentry **tblp;
+	struct tblentry **pp;
+	struct tblentry *cmdp;
+
+	INTOFF;
+	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
+		pp = tblp;
+		while ((cmdp = *pp) != NULL) {
+			if (cmdp->cmdtype == CMDNORMAL) {
+				*pp = cmdp->next;
+				ckfree(cmdp);
+			} else {
+				pp = &cmdp->next;
+			}
+		}
+	}
+	cmdtable_cd = 0;
+	INTON;
+}
+
+
+/*
+ * Locate a command in the command hash table.  If "add" is nonzero,
+ * add the command to the table if it is not already present.  The
+ * variable "lastcmdentry" is set to point to the address of the link
+ * pointing to the entry, so that delete_cmd_entry can delete the
+ * entry.
+ */
+
+static struct tblentry **lastcmdentry;
+
+
+static struct tblentry *
+cmdlookup(const char *name, int add)
+{
+	unsigned int hashval;
+	const char *p;
+	struct tblentry *cmdp;
+	struct tblentry **pp;
+	size_t len;
+
+	p = name;
+	hashval = (unsigned char)*p << 4;
+	while (*p)
+		hashval += *p++;
+	pp = &cmdtable[hashval % CMDTABLESIZE];
+	for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
+		if (equal(cmdp->cmdname, name))
+			break;
+		pp = &cmdp->next;
+	}
+	if (add && cmdp == NULL) {
+		INTOFF;
+		len = strlen(name);
+		cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1);
+		cmdp->next = NULL;
+		cmdp->cmdtype = CMDUNKNOWN;
+		memcpy(cmdp->cmdname, name, len + 1);
+		INTON;
+	}
+	lastcmdentry = pp;
+	return cmdp;
+}
+
+/*
+ * Delete the command entry returned on the last lookup.
+ */
+
+static void
+delete_cmd_entry(void)
+{
+	struct tblentry *cmdp;
+
+	INTOFF;
+	cmdp = *lastcmdentry;
+	*lastcmdentry = cmdp->next;
+	ckfree(cmdp);
+	INTON;
+}
+
+
+
+/*
+ * Add a new command entry, replacing any existing command entry for
+ * the same name.
+ */
+
+static void
+addcmdentry(const char *name, struct cmdentry *entry)
+{
+	struct tblentry *cmdp;
+
+	INTOFF;
+	cmdp = cmdlookup(name, 1);
+	if (cmdp->cmdtype == CMDFUNCTION) {
+		unreffunc(cmdp->param.func);
+	}
+	cmdp->cmdtype = entry->cmdtype;
+	cmdp->param = entry->u;
+	cmdp->special = entry->special;
+	INTON;
+}
+
+
+/*
+ * Define a shell function.
+ */
+
+void
+defun(const char *name, union node *func)
+{
+	struct cmdentry entry;
+
+	INTOFF;
+	entry.cmdtype = CMDFUNCTION;
+	entry.u.func = copyfunc(func);
+	entry.special = 0;
+	addcmdentry(name, &entry);
+	INTON;
+}
+
+
+/*
+ * Delete a function if it exists.
+ * Called with interrupts off.
+ */
+
+int
+unsetfunc(const char *name)
+{
+	struct tblentry *cmdp;
+
+	if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
+		unreffunc(cmdp->param.func);
+		delete_cmd_entry();
+		return (0);
+	}
+	return (0);
+}
+
+
+/*
+ * Check if a function by a certain name exists.
+ */
+int
+isfunc(const char *name)
+{
+	struct tblentry *cmdp;
+	cmdp = cmdlookup(name, 0);
+	return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
+}
+
+
+/*
+ * Shared code for the following builtin commands:
+ *    type, command -v, command -V
+ */
+
+int
+typecmd_impl(int argc, char **argv, int cmd, const char *path)
+{
+	struct cmdentry entry;
+	struct tblentry *cmdp;
+	const char *const *pp;
+	struct alias *ap;
+	int i;
+	int error1 = 0;
+
+	if (path != pathval())
+		clearcmdentry();
+
+	for (i = 1; i < argc; i++) {
+		/* First look at the keywords */
+		for (pp = parsekwd; *pp; pp++)
+			if (**pp == *argv[i] && equal(*pp, argv[i]))
+				break;
+
+		if (*pp) {
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else
+				out1fmt("%s is a shell keyword\n", argv[i]);
+			continue;
+		}
+
+		/* Then look at the aliases */
+		if ((ap = lookupalias(argv[i], 1)) != NULL) {
+			if (cmd == TYPECMD_SMALLV) {
+				out1fmt("alias %s=", argv[i]);
+				out1qstr(ap->val);
+				outcslow('\n', out1);
+			} else
+				out1fmt("%s is an alias for %s\n", argv[i],
+				    ap->val);
+			continue;
+		}
+
+		/* Then check if it is a tracked alias */
+		if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
+			entry.cmdtype = cmdp->cmdtype;
+			entry.u = cmdp->param;
+			entry.special = cmdp->special;
+		}
+		else {
+			/* Finally use brute force */
+			find_command(argv[i], &entry, 0, path);
+		}
+
+		switch (entry.cmdtype) {
+		case CMDNORMAL: {
+			if (strchr(argv[i], '/') == NULL) {
+				const char *path2 = path;
+				const char *opt2;
+				char *name;
+				int j = entry.u.index;
+				do {
+					name = padvance(&path2, &opt2, argv[i]);
+					stunalloc(name);
+				} while (--j >= 0);
+				if (cmd == TYPECMD_SMALLV)
+					out1fmt("%s\n", name);
+				else
+					out1fmt("%s is%s %s\n", argv[i],
+					    (cmdp && cmd == TYPECMD_TYPE) ?
+						" a tracked alias for" : "",
+					    name);
+			} else {
+				if (faccessat(AT_FDCWD, argv[i], X_OK, AT_EACCESS) == 0) {
+					if (cmd == TYPECMD_SMALLV)
+						out1fmt("%s\n", argv[i]);
+					else
+						out1fmt("%s is %s\n", argv[i],
+						    argv[i]);
+				} else {
+					if (cmd != TYPECMD_SMALLV)
+						outfmt(out2, "%s: %s\n",
+						    argv[i], strerror(errno));
+					error1 |= 127;
+				}
+			}
+			break;
+		}
+		case CMDFUNCTION:
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else
+				out1fmt("%s is a shell function\n", argv[i]);
+			break;
+
+		case CMDBUILTIN:
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else if (entry.special)
+				out1fmt("%s is a special shell builtin\n",
+				    argv[i]);
+			else
+				out1fmt("%s is a shell builtin\n", argv[i]);
+			break;
+
+		default:
+			if (cmd != TYPECMD_SMALLV)
+				outfmt(out2, "%s: not found\n", argv[i]);
+			error1 |= 127;
+			break;
+		}
+	}
+
+	if (path != pathval())
+		clearcmdentry();
+
+	return error1;
+}
+
+/*
+ * Locate and print what a word is...
+ */
+
+int
+typecmd(int argc, char **argv)
+{
+	if (argc > 2 && strcmp(argv[1], "--") == 0)
+		argc--, argv++;
+	return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));
+}
diff --git a/bin/1sh/exec.h b/bin/1sh/exec.h
new file mode 100644
index 00000000..f93c14c2
--- /dev/null
+++ b/bin/1sh/exec.h
@@ -0,0 +1,76 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)exec.h	8.3 (Berkeley) 6/8/95
+ * $FreeBSD: releng/12.1/bin/sh/exec.h 336320 2018-07-15 21:55:17Z jilles $
+ */
+
+/* values of cmdtype */
+#define CMDUNKNOWN -1		/* no entry in table for command */
+#define CMDNORMAL 0		/* command is an executable program */
+#define CMDBUILTIN 1		/* command is a shell builtin */
+#define CMDFUNCTION 2		/* command is a shell function */
+
+/* values for typecmd_impl's third parameter */
+enum {
+	TYPECMD_SMALLV,		/* command -v */
+	TYPECMD_BIGV,		/* command -V */
+	TYPECMD_TYPE		/* type */
+};
+
+union node;
+struct cmdentry {
+	int cmdtype;
+	union param {
+		int index;
+		struct funcdef *func;
+	} u;
+	int special;
+};
+
+
+/* action to find_command() */
+#define DO_ERR		0x01	/* prints errors */
+#define DO_NOFUNC	0x02	/* don't return shell functions, for command */
+
+extern int exerrno;		/* last exec error */
+
+void shellexec(char **, char **, const char *, int) __attribute__((noreturn));
+char *padvance(const char **, const char **, const char *);
+void find_command(const char *, struct cmdentry *, int, const char *);
+int find_builtin(const char *, int *);
+void hashcd(void);
+void changepath(const char *);
+void defun(const char *, union node *);
+int unsetfunc(const char *);
+int isfunc(const char *);
+int typecmd_impl(int, char **, int, const char *);
+void clearcmdentry(void);
diff --git a/bin/1sh/expand.c b/bin/1sh/expand.c
new file mode 100644
index 00000000..3bdd0733
--- /dev/null
+++ b/bin/1sh/expand.c
@@ -0,0 +1,1553 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1997-2005
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ * Copyright (c) 2010-2015
+ *	Jilles Tjoelker <jilles@stack.nl>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)expand.c	8.5 (Berkeley) 5/15/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/expand.c 341767 2018-12-09 19:14:21Z jilles $ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wchar.h>
+#include <wctype.h>
+
+/*
+ * Routines to expand arguments to commands.  We have to deal with
+ * backquotes, shell variables, and file metacharacters.
+ */
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"
+#include "eval.h"
+#include "expand.h"
+#include "syntax.h"
+#include "parser.h"
+#include "jobs.h"
+#include "options.h"
+#include "var.h"
+#include "input.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "arith.h"
+#include "show.h"
+#include "builtins.h"
+
+enum wordstate { WORD_IDLE, WORD_WS_DELIMITED, WORD_QUOTEMARK };
+
+struct worddest {
+	struct arglist *list;
+	enum wordstate state;
+};
+
+static char *expdest;			/* output of current string */
+
+static const char *argstr(const char *, struct nodelist **restrict, int,
+    struct worddest *);
+static const char *exptilde(const char *, int);
+static const char *expari(const char *, struct nodelist **restrict, int,
+    struct worddest *);
+static void expbackq(union node *, int, int, struct worddest *);
+static const char *subevalvar_trim(const char *, struct nodelist **restrict,
+    int, int, int);
+static const char *subevalvar_misc(const char *, struct nodelist **restrict,
+    const char *, int, int, int);
+static const char *evalvar(const char *, struct nodelist **restrict, int,
+    struct worddest *);
+static int varisset(const char *, int);
+static void strtodest(const char *, int, int, int, struct worddest *);
+static void reprocess(int, int, int, int, struct worddest *);
+static void varvalue(const char *, int, int, int, struct worddest *);
+static void expandmeta(char *, struct arglist *);
+static void expmeta(char *, char *, struct arglist *);
+static int expsortcmp(const void *, const void *);
+static int patmatch(const char *, const char *);
+static void cvtnum(int, char *);
+static int collate_range_cmp(wchar_t, wchar_t);
+
+void
+emptyarglist(struct arglist *list)
+{
+
+	list->args = list->smallarg;
+	list->count = 0;
+	list->capacity = sizeof(list->smallarg) / sizeof(list->smallarg[0]);
+}
+
+void
+appendarglist(struct arglist *list, char *str)
+{
+	char **newargs;
+	int newcapacity;
+
+	if (list->count >= list->capacity) {
+		newcapacity = list->capacity * 2;
+		if (newcapacity < 16)
+			newcapacity = 16;
+		if (newcapacity > INT_MAX / (int)sizeof(newargs[0]))
+			error("Too many entries in arglist");
+		newargs = stalloc(newcapacity * sizeof(newargs[0]));
+		memcpy(newargs, list->args, list->count * sizeof(newargs[0]));
+		list->args = newargs;
+		list->capacity = newcapacity;
+	}
+	list->args[list->count++] = str;
+}
+
+static int
+collate_range_cmp(wchar_t c1, wchar_t c2)
+{
+	wchar_t s1[2], s2[2];
+
+	s1[0] = c1;
+	s1[1] = L'\0';
+	s2[0] = c2;
+	s2[1] = L'\0';
+	return (wcscoll(s1, s2));
+}
+
+static char *
+stputs_quotes(const char *data, const char *syntax, char *p)
+{
+	while (*data) {
+		CHECKSTRSPACE(2, p);
+		if (syntax[(int)*data] == CCTL)
+			USTPUTC(CTLESC, p);
+		USTPUTC(*data++, p);
+	}
+	return (p);
+}
+#define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
+
+static char *
+nextword(char c, int flag, char *p, struct worddest *dst)
+{
+	int is_ws;
+
+	is_ws = c == '\t' || c == '\n' || c == ' ';
+	if (p != stackblock() || (is_ws ? dst->state == WORD_QUOTEMARK :
+	    dst->state != WORD_WS_DELIMITED) || c == '\0') {
+		STPUTC('\0', p);
+		if (flag & EXP_GLOB)
+			expandmeta(grabstackstr(p), dst->list);
+		else
+			appendarglist(dst->list, grabstackstr(p));
+		dst->state = is_ws ? WORD_WS_DELIMITED : WORD_IDLE;
+	} else if (!is_ws && dst->state == WORD_WS_DELIMITED)
+		dst->state = WORD_IDLE;
+	/* Reserve space while the stack string is empty. */
+	appendarglist(dst->list, NULL);
+	dst->list->count--;
+	STARTSTACKSTR(p);
+	return p;
+}
+#define NEXTWORD(c, flag, p, dstlist) p = nextword(c, flag, p, dstlist)
+
+static char *
+stputs_split(const char *data, const char *syntax, int flag, char *p,
+    struct worddest *dst)
+{
+	const char *ifs;
+	char c;
+
+	ifs = ifsset() ? ifsval() : " \t\n";
+	while (*data) {
+		CHECKSTRSPACE(2, p);
+		c = *data++;
+		if (strchr(ifs, c) != NULL) {
+			NEXTWORD(c, flag, p, dst);
+			continue;
+		}
+		if (flag & EXP_GLOB && syntax[(int)c] == CCTL)
+			USTPUTC(CTLESC, p);
+		USTPUTC(c, p);
+	}
+	return (p);
+}
+#define STPUTS_SPLIT(data, syntax, flag, p, dst) p = stputs_split((data), syntax, flag, p, dst)
+
+/*
+ * Perform expansions on an argument, placing the resulting list of arguments
+ * in arglist.  Parameter expansion, command substitution and arithmetic
+ * expansion are always performed; additional expansions can be requested
+ * via flag (EXP_*).
+ * The result is left in the stack string.
+ * When arglist is NULL, perform here document expansion.
+ *
+ * When doing something that may cause this to be re-entered, make sure
+ * the stack string is empty via grabstackstr() and do not assume expdest
+ * remains valid.
+ */
+void
+expandarg(union node *arg, struct arglist *arglist, int flag)
+{
+	struct worddest exparg;
+	struct nodelist *argbackq;
+
+	if (fflag)
+		flag &= ~EXP_GLOB;
+	argbackq = arg->narg.backquote;
+	exparg.list = arglist;
+	exparg.state = WORD_IDLE;
+	STARTSTACKSTR(expdest);
+	argstr(arg->narg.text, &argbackq, flag, &exparg);
+	if (arglist == NULL) {
+		STACKSTRNUL(expdest);
+		return;			/* here document expanded */
+	}
+	if ((flag & EXP_SPLIT) == 0 || expdest != stackblock() ||
+	    exparg.state == WORD_QUOTEMARK) {
+		STPUTC('\0', expdest);
+		if (flag & EXP_SPLIT) {
+			if (flag & EXP_GLOB)
+				expandmeta(grabstackstr(expdest), exparg.list);
+			else
+				appendarglist(exparg.list, grabstackstr(expdest));
+		}
+	}
+	if ((flag & EXP_SPLIT) == 0)
+		appendarglist(arglist, grabstackstr(expdest));
+}
+
+
+
+/*
+ * Perform parameter expansion, command substitution and arithmetic
+ * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
+ * Processing ends at a CTLENDVAR or CTLENDARI character as well as '\0'.
+ * This is used to expand word in ${var+word} etc.
+ * If EXP_GLOB or EXP_CASE are set, keep and/or generate CTLESC
+ * characters to allow for further processing.
+ *
+ * If EXP_SPLIT is set, dst receives any complete words produced.
+ */
+static const char *
+argstr(const char *p, struct nodelist **restrict argbackq, int flag,
+    struct worddest *dst)
+{
+	char c;
+	int quotes = flag & (EXP_GLOB | EXP_CASE);	/* do CTLESC */
+	int firsteq = 1;
+	int split_lit;
+	int lit_quoted;
+
+	split_lit = flag & EXP_SPLIT_LIT;
+	lit_quoted = flag & EXP_LIT_QUOTED;
+	flag &= ~(EXP_SPLIT_LIT | EXP_LIT_QUOTED);
+	if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
+		p = exptilde(p, flag);
+	for (;;) {
+		CHECKSTRSPACE(2, expdest);
+		switch (c = *p++) {
+		case '\0':
+			return (p - 1);
+		case CTLENDVAR:
+		case CTLENDARI:
+			return (p);
+		case CTLQUOTEMARK:
+			lit_quoted = 1;
+			/* "$@" syntax adherence hack */
+			if (p[0] == CTLVAR && (p[1] & VSQUOTE) != 0 &&
+			    p[2] == '@' && p[3] == '=')
+				break;
+			if ((flag & EXP_SPLIT) != 0 && expdest == stackblock())
+				dst->state = WORD_QUOTEMARK;
+			break;
+		case CTLQUOTEEND:
+			lit_quoted = 0;
+			break;
+		case CTLESC:
+			c = *p++;
+			if (split_lit && !lit_quoted &&
+			    strchr(ifsset() ? ifsval() : " \t\n", c) != NULL) {
+				NEXTWORD(c, flag, expdest, dst);
+				break;
+			}
+			if (quotes)
+				USTPUTC(CTLESC, expdest);
+			USTPUTC(c, expdest);
+			break;
+		case CTLVAR:
+			p = evalvar(p, argbackq, flag, dst);
+			break;
+		case CTLBACKQ:
+		case CTLBACKQ|CTLQUOTE:
+			expbackq((*argbackq)->n, c & CTLQUOTE, flag, dst);
+			*argbackq = (*argbackq)->next;
+			break;
+		case CTLARI:
+			p = expari(p, argbackq, flag, dst);
+			break;
+		case ':':
+		case '=':
+			/*
+			 * sort of a hack - expand tildes in variable
+			 * assignments (after the first '=' and after ':'s).
+			 */
+			if (split_lit && !lit_quoted &&
+			    strchr(ifsset() ? ifsval() : " \t\n", c) != NULL) {
+				NEXTWORD(c, flag, expdest, dst);
+				break;
+			}
+			USTPUTC(c, expdest);
+			if (flag & EXP_VARTILDE && *p == '~' &&
+			    (c != '=' || firsteq)) {
+				if (c == '=')
+					firsteq = 0;
+				p = exptilde(p, flag);
+			}
+			break;
+		default:
+			if (split_lit && !lit_quoted &&
+			    strchr(ifsset() ? ifsval() : " \t\n", c) != NULL) {
+				NEXTWORD(c, flag, expdest, dst);
+				break;
+			}
+			USTPUTC(c, expdest);
+		}
+	}
+}
+
+/*
+ * Perform tilde expansion, placing the result in the stack string and
+ * returning the next position in the input string to process.
+ */
+static const char *
+exptilde(const char *p, int flag)
+{
+	char c;
+	const char *startp = p;
+	const char *user;
+	struct passwd *pw;
+	char *home;
+	int len;
+
+	for (;;) {
+		c = *p;
+		switch(c) {
+		case CTLESC: /* This means CTL* are always considered quoted. */
+		case CTLVAR:
+		case CTLBACKQ:
+		case CTLBACKQ | CTLQUOTE:
+		case CTLARI:
+		case CTLENDARI:
+		case CTLQUOTEMARK:
+			return (startp);
+		case ':':
+			if ((flag & EXP_VARTILDE) == 0)
+				break;
+			/* FALLTHROUGH */
+		case '\0':
+		case '/':
+		case CTLENDVAR:
+			len = p - startp - 1;
+			STPUTBIN(startp + 1, len, expdest);
+			STACKSTRNUL(expdest);
+			user = expdest - len;
+			if (*user == '\0') {
+				home = lookupvar("HOME");
+			} else {
+				pw = getpwnam(user);
+				home = pw != NULL ? pw->pw_dir : NULL;
+			}
+			STADJUST(-len, expdest);
+			if (home == NULL || *home == '\0')
+				return (startp);
+			strtodest(home, flag, VSNORMAL, 1, NULL);
+			return (p);
+		}
+		p++;
+	}
+}
+
+
+/*
+ * Expand arithmetic expression.
+ */
+static const char *
+expari(const char *p, struct nodelist **restrict argbackq, int flag,
+    struct worddest *dst)
+{
+	char *q, *start;
+	arith_t result;
+	int begoff;
+	int quoted;
+	int adj;
+
+	quoted = *p++ == '"';
+	begoff = expdest - stackblock();
+	p = argstr(p, argbackq, 0, NULL);
+	STPUTC('\0', expdest);
+	start = stackblock() + begoff;
+
+	q = grabstackstr(expdest);
+	result = arith(start);
+	ungrabstackstr(q, expdest);
+
+	start = stackblock() + begoff;
+	adj = start - expdest;
+	STADJUST(adj, expdest);
+
+	CHECKSTRSPACE((int)(DIGITS(result) + 1), expdest);
+	fmtstr(expdest, DIGITS(result), ARITH_FORMAT_STR, result);
+	adj = strlen(expdest);
+	STADJUST(adj, expdest);
+	/*
+	 * If this is quoted, a '-' must not indicate a range in [...].
+	 * If this is not quoted, splitting may occur.
+	 */
+	if (quoted ?
+	    result < 0 && begoff > 1 && flag & (EXP_GLOB | EXP_CASE) :
+	    flag & EXP_SPLIT)
+		reprocess(expdest - adj - stackblock(), flag, VSNORMAL, quoted,
+		    dst);
+	return p;
+}
+
+
+/*
+ * Perform command substitution.
+ */
+static void
+expbackq(union node *cmd, int quoted, int flag, struct worddest *dst)
+{
+	struct backcmd in;
+	int i;
+	char buf[128];
+	char *p;
+	char *dest = expdest;
+	char lastc;
+	char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
+	int quotes = flag & (EXP_GLOB | EXP_CASE);
+	size_t nnl;
+	const char *ifs;
+	int startloc;
+
+	INTOFF;
+	p = grabstackstr(dest);
+	evalbackcmd(cmd, &in);
+	ungrabstackstr(p, dest);
+
+	p = in.buf;
+	startloc = dest - stackblock();
+	nnl = 0;
+	if (!quoted && flag & EXP_SPLIT)
+		ifs = ifsset() ? ifsval() : " \t\n";
+	else
+		ifs = "";
+	/* Remove trailing newlines */
+	for (;;) {
+		if (--in.nleft < 0) {
+			if (in.fd < 0)
+				break;
+			while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR)
+				;
+			TRACE(("expbackq: read returns %d\n", i));
+			if (i <= 0)
+				break;
+			p = buf;
+			in.nleft = i - 1;
+		}
+		lastc = *p++;
+		if (lastc == '\0')
+			continue;
+		if (nnl > 0 && lastc != '\n') {
+			NEXTWORD('\n', flag, dest, dst);
+			nnl = 0;
+		}
+		if (strchr(ifs, lastc) != NULL) {
+			if (lastc == '\n')
+				nnl++;
+			else
+				NEXTWORD(lastc, flag, dest, dst);
+		} else {
+			CHECKSTRSPACE(2, dest);
+			if (quotes && syntax[(int)lastc] == CCTL)
+				USTPUTC(CTLESC, dest);
+			USTPUTC(lastc, dest);
+		}
+	}
+	while (dest > stackblock() + startloc && STTOPC(dest) == '\n')
+		STUNPUTC(dest);
+
+	if (in.fd >= 0)
+		close(in.fd);
+	if (in.buf)
+		ckfree(in.buf);
+	if (in.jp) {
+		p = grabstackstr(dest);
+		exitstatus = waitforjob(in.jp, (int *)NULL);
+		ungrabstackstr(p, dest);
+	}
+	TRACE(("expbackq: done\n"));
+	expdest = dest;
+	INTON;
+}
+
+
+
+static void
+recordleft(const char *str, const char *loc, char *startp)
+{
+	int amount;
+
+	amount = ((str - 1) - (loc - startp)) - expdest;
+	STADJUST(amount, expdest);
+	while (loc != str - 1)
+		*startp++ = *loc++;
+}
+
+static const char *
+subevalvar_trim(const char *p, struct nodelist **restrict argbackq, int strloc,
+    int subtype, int startloc)
+{
+	char *startp;
+	char *loc = NULL;
+	char *str;
+	int c = 0;
+	int amount;
+
+	p = argstr(p, argbackq, EXP_CASE | EXP_TILDE, NULL);
+	STACKSTRNUL(expdest);
+	startp = stackblock() + startloc;
+	str = stackblock() + strloc;
+
+	switch (subtype) {
+	case VSTRIMLEFT:
+		for (loc = startp; loc < str; loc++) {
+			c = *loc;
+			*loc = '\0';
+			if (patmatch(str, startp)) {
+				*loc = c;
+				recordleft(str, loc, startp);
+				return p;
+			}
+			*loc = c;
+		}
+		break;
+
+	case VSTRIMLEFTMAX:
+		for (loc = str - 1; loc >= startp;) {
+			c = *loc;
+			*loc = '\0';
+			if (patmatch(str, startp)) {
+				*loc = c;
+				recordleft(str, loc, startp);
+				return p;
+			}
+			*loc = c;
+			loc--;
+		}
+		break;
+
+	case VSTRIMRIGHT:
+		for (loc = str - 1; loc >= startp;) {
+			if (patmatch(str, loc)) {
+				amount = loc - expdest;
+				STADJUST(amount, expdest);
+				return p;
+			}
+			loc--;
+		}
+		break;
+
+	case VSTRIMRIGHTMAX:
+		for (loc = startp; loc < str - 1; loc++) {
+			if (patmatch(str, loc)) {
+				amount = loc - expdest;
+				STADJUST(amount, expdest);
+				return p;
+			}
+		}
+		break;
+
+
+	default:
+		abort();
+	}
+	amount = (expdest - stackblock() - strloc) + 1;
+	STADJUST(-amount, expdest);
+	return p;
+}
+
+
+static const char *
+subevalvar_misc(const char *p, struct nodelist **restrict argbackq,
+    const char *var, int subtype, int startloc, int varflags)
+{
+	const char *end;
+	char *startp;
+	int amount;
+
+	end = argstr(p, argbackq, EXP_TILDE, NULL);
+	STACKSTRNUL(expdest);
+	startp = stackblock() + startloc;
+
+	switch (subtype) {
+	case VSASSIGN:
+		setvar(var, startp, 0);
+		amount = startp - expdest;
+		STADJUST(amount, expdest);
+		return end;
+
+	case VSQUESTION:
+		if (*p != CTLENDVAR) {
+			outfmt(out2, "%s\n", startp);
+			error((char *)NULL);
+		}
+		error("%.*s: parameter %snot set", (int)(p - var - 1),
+		      var, (varflags & VSNUL) ? "null or " : "");
+
+	default:
+		abort();
+	}
+}
+
+
+/*
+ * Expand a variable, and return a pointer to the next character in the
+ * input string.
+ */
+
+static const char *
+evalvar(const char *p, struct nodelist **restrict argbackq, int flag,
+    struct worddest *dst)
+{
+	int subtype;
+	int varflags;
+	const char *var;
+	const char *val;
+	int patloc;
+	int c;
+	int set;
+	int special;
+	int startloc;
+	int varlen;
+	int varlenb;
+	char buf[21];
+
+	varflags = (unsigned char)*p++;
+	subtype = varflags & VSTYPE;
+	var = p;
+	special = 0;
+	if (! is_name(*p))
+		special = 1;
+	p = strchr(p, '=') + 1;
+	if (varflags & VSLINENO) {
+		set = 1;
+		special = 1;
+		val = NULL;
+	} else if (special) {
+		set = varisset(var, varflags & VSNUL);
+		val = NULL;
+	} else {
+		val = bltinlookup(var, 1);
+		if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
+			val = NULL;
+			set = 0;
+		} else
+			set = 1;
+	}
+	varlen = 0;
+	startloc = expdest - stackblock();
+	if (!set && uflag && *var != '@' && *var != '*') {
+		switch (subtype) {
+		case VSNORMAL:
+		case VSTRIMLEFT:
+		case VSTRIMLEFTMAX:
+		case VSTRIMRIGHT:
+		case VSTRIMRIGHTMAX:
+		case VSLENGTH:
+			error("%.*s: parameter not set", (int)(p - var - 1),
+			    var);
+		}
+	}
+	if (set && subtype != VSPLUS) {
+		/* insert the value of the variable */
+		if (special) {
+			if (varflags & VSLINENO) {
+				if (p - var > (ptrdiff_t)sizeof(buf))
+					abort();
+				memcpy(buf, var, p - var - 1);
+				buf[p - var - 1] = '\0';
+				strtodest(buf, flag, subtype,
+				    varflags & VSQUOTE, dst);
+			} else
+				varvalue(var, varflags & VSQUOTE, subtype, flag,
+				    dst);
+			if (subtype == VSLENGTH) {
+				varlenb = expdest - stackblock() - startloc;
+				varlen = varlenb;
+				if (localeisutf8) {
+					val = stackblock() + startloc;
+					for (;val != expdest; val++)
+						if ((*val & 0xC0) == 0x80)
+							varlen--;
+				}
+				STADJUST(-varlenb, expdest);
+			}
+		} else {
+			if (subtype == VSLENGTH) {
+				for (;*val; val++)
+					if (!localeisutf8 ||
+					    (*val & 0xC0) != 0x80)
+						varlen++;
+			}
+			else
+				strtodest(val, flag, subtype,
+				    varflags & VSQUOTE, dst);
+		}
+	}
+
+	if (subtype == VSPLUS)
+		set = ! set;
+
+	switch (subtype) {
+	case VSLENGTH:
+		cvtnum(varlen, buf);
+		strtodest(buf, flag, VSNORMAL, varflags & VSQUOTE, dst);
+		break;
+
+	case VSNORMAL:
+		return p;
+
+	case VSPLUS:
+	case VSMINUS:
+		if (!set) {
+			return argstr(p, argbackq,
+			    flag | (flag & EXP_SPLIT ? EXP_SPLIT_LIT : 0) |
+			    (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0), dst);
+		}
+		break;
+
+	case VSTRIMLEFT:
+	case VSTRIMLEFTMAX:
+	case VSTRIMRIGHT:
+	case VSTRIMRIGHTMAX:
+		if (!set)
+			break;
+		/*
+		 * Terminate the string and start recording the pattern
+		 * right after it
+		 */
+		STPUTC('\0', expdest);
+		patloc = expdest - stackblock();
+		p = subevalvar_trim(p, argbackq, patloc, subtype, startloc);
+		reprocess(startloc, flag, VSNORMAL, varflags & VSQUOTE, dst);
+		if (flag & EXP_SPLIT && *var == '@' && varflags & VSQUOTE)
+			dst->state = WORD_QUOTEMARK;
+		return p;
+
+	case VSASSIGN:
+	case VSQUESTION:
+		if (!set) {
+			p = subevalvar_misc(p, argbackq, var, subtype,
+			    startloc, varflags);
+			/* assert(subtype == VSASSIGN); */
+			val = lookupvar(var);
+			strtodest(val, flag, subtype, varflags & VSQUOTE, dst);
+			return p;
+		}
+		break;
+
+	case VSERROR:
+		c = p - var - 1;
+		error("${%.*s%s}: Bad substitution", c, var,
+		    (c > 0 && *p != CTLENDVAR) ? "..." : "");
+
+	default:
+		abort();
+	}
+
+	{	/* skip to end of alternative */
+		int nesting = 1;
+		for (;;) {
+			if ((c = *p++) == CTLESC)
+				p++;
+			else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE))
+				*argbackq = (*argbackq)->next;
+			else if (c == CTLVAR) {
+				if ((*p++ & VSTYPE) != VSNORMAL)
+					nesting++;
+			} else if (c == CTLENDVAR) {
+				if (--nesting == 0)
+					break;
+			}
+		}
+	}
+	return p;
+}
+
+
+
+/*
+ * Test whether a special or positional parameter is set.
+ */
+
+static int
+varisset(const char *name, int nulok)
+{
+
+	if (*name == '!')
+		return backgndpidset();
+	else if (*name == '@' || *name == '*') {
+		if (*shellparam.p == NULL)
+			return 0;
+
+		if (nulok) {
+			char **av;
+
+			for (av = shellparam.p; *av; av++)
+				if (**av != '\0')
+					return 1;
+			return 0;
+		}
+	} else if (is_digit(*name)) {
+		char *ap;
+		long num;
+
+		errno = 0;
+		num = strtol(name, NULL, 10);
+		if (errno != 0 || num > shellparam.nparam)
+			return 0;
+
+		if (num == 0)
+			ap = arg0;
+		else
+			ap = shellparam.p[num - 1];
+
+		if (nulok && (ap == NULL || *ap == '\0'))
+			return 0;
+	}
+	return 1;
+}
+
+static void
+strtodest(const char *p, int flag, int subtype, int quoted,
+    struct worddest *dst)
+{
+	if (subtype == VSLENGTH || subtype == VSTRIMLEFT ||
+	    subtype == VSTRIMLEFTMAX || subtype == VSTRIMRIGHT ||
+	    subtype == VSTRIMRIGHTMAX)
+		STPUTS(p, expdest);
+	else if (flag & EXP_SPLIT && !quoted && dst != NULL)
+		STPUTS_SPLIT(p, BASESYNTAX, flag, expdest, dst);
+	else if (flag & (EXP_GLOB | EXP_CASE))
+		STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
+	else
+		STPUTS(p, expdest);
+}
+
+static void
+reprocess(int startloc, int flag, int subtype, int quoted,
+    struct worddest *dst)
+{
+	static char *buf = NULL;
+	static size_t buflen = 0;
+	char *startp;
+	size_t len, zpos, zlen;
+
+	startp = stackblock() + startloc;
+	len = expdest - startp;
+	if (len >= SIZE_MAX / 2 || len > PTRDIFF_MAX)
+		abort();
+	INTOFF;
+	if (len >= buflen) {
+		ckfree(buf);
+		buf = NULL;
+	}
+	if (buflen < 128)
+		buflen = 128;
+	while (len >= buflen)
+		buflen <<= 1;
+	if (buf == NULL)
+		buf = ckmalloc(buflen);
+	INTON;
+	memcpy(buf, startp, len);
+	buf[len] = '\0';
+	STADJUST(-(ptrdiff_t)len, expdest);
+	for (zpos = 0;;) {
+		zlen = strlen(buf + zpos);
+		strtodest(buf + zpos, flag, subtype, quoted, dst);
+		zpos += zlen + 1;
+		if (zpos == len + 1)
+			break;
+		if (flag & EXP_SPLIT && (quoted || (zlen > 0 && zpos < len)))
+			NEXTWORD('\0', flag, expdest, dst);
+	}
+}
+
+/*
+ * Add the value of a special or positional parameter to the stack string.
+ */
+
+static void
+varvalue(const char *name, int quoted, int subtype, int flag,
+    struct worddest *dst)
+{
+	int num;
+	char *p;
+	int i;
+	int splitlater;
+	char sep[2];
+	char **ap;
+	char buf[(NSHORTOPTS > 10 ? NSHORTOPTS : 10) + 1];
+
+	if (subtype == VSLENGTH)
+		flag &= ~EXP_FULL;
+	splitlater = subtype == VSTRIMLEFT || subtype == VSTRIMLEFTMAX ||
+		subtype == VSTRIMRIGHT || subtype == VSTRIMRIGHTMAX;
+
+	switch (*name) {
+	case '$':
+		num = rootpid;
+		break;
+	case '?':
+		num = oexitstatus;
+		break;
+	case '#':
+		num = shellparam.nparam;
+		break;
+	case '!':
+		num = backgndpidval();
+		break;
+	case '-':
+		p = buf;
+		for (i = 0 ; i < NSHORTOPTS ; i++) {
+			if (optval[i])
+				*p++ = optletter[i];
+		}
+		*p = '\0';
+		strtodest(buf, flag, subtype, quoted, dst);
+		return;
+	case '@':
+		if (flag & EXP_SPLIT && quoted) {
+			for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
+				strtodest(p, flag, subtype, quoted, dst);
+				if (*ap) {
+					if (splitlater)
+						STPUTC('\0', expdest);
+					else
+						NEXTWORD('\0', flag, expdest,
+						    dst);
+				}
+			}
+			if (shellparam.nparam > 0)
+				dst->state = WORD_QUOTEMARK;
+			return;
+		}
+		/* FALLTHROUGH */
+	case '*':
+		if (ifsset())
+			sep[0] = ifsval()[0];
+		else
+			sep[0] = ' ';
+		sep[1] = '\0';
+		for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
+			strtodest(p, flag, subtype, quoted, dst);
+			if (!*ap)
+				break;
+			if (sep[0])
+				strtodest(sep, flag, subtype, quoted, dst);
+			else if (flag & EXP_SPLIT && !quoted && **ap != '\0') {
+				if (splitlater)
+					STPUTC('\0', expdest);
+				else
+					NEXTWORD('\0', flag, expdest, dst);
+			}
+		}
+		return;
+	default:
+		if (is_digit(*name)) {
+			num = atoi(name);
+			if (num == 0)
+				p = arg0;
+			else if (num > 0 && num <= shellparam.nparam)
+				p = shellparam.p[num - 1];
+			else
+				return;
+			strtodest(p, flag, subtype, quoted, dst);
+		}
+		return;
+	}
+	cvtnum(num, buf);
+	strtodest(buf, flag, subtype, quoted, dst);
+}
+
+
+
+static char expdir[PATH_MAX];
+#define expdir_end (expdir + sizeof(expdir))
+
+/*
+ * Perform pathname generation and remove control characters.
+ * At this point, the only control characters should be CTLESC.
+ * The results are stored in the list dstlist.
+ */
+static void
+expandmeta(char *pattern, struct arglist *dstlist)
+{
+	char *p;
+	int firstmatch;
+	char c;
+
+	firstmatch = dstlist->count;
+	p = pattern;
+	for (; (c = *p) != '\0'; p++) {
+		/* fast check for meta chars */
+		if (c == '*' || c == '?' || c == '[') {
+			INTOFF;
+			expmeta(expdir, pattern, dstlist);
+			INTON;
+			break;
+		}
+	}
+	if (dstlist->count == firstmatch) {
+		/*
+		 * no matches
+		 */
+		rmescapes(pattern);
+		appendarglist(dstlist, pattern);
+	} else {
+		qsort(&dstlist->args[firstmatch],
+		    dstlist->count - firstmatch,
+		    sizeof(dstlist->args[0]), expsortcmp);
+	}
+}
+
+
+/*
+ * Do metacharacter (i.e. *, ?, [...]) expansion.
+ */
+
+static void
+expmeta(char *enddir, char *name, struct arglist *arglist)
+{
+	const char *p;
+	const char *q;
+	const char *start;
+	char *endname;
+	int metaflag;
+	struct stat statb;
+	DIR *dirp;
+	struct dirent *dp;
+	int atend;
+	int matchdot;
+	int esc;
+	int namlen;
+
+	metaflag = 0;
+	start = name;
+	for (p = name; esc = 0, *p; p += esc + 1) {
+		if (*p == '*' || *p == '?')
+			metaflag = 1;
+		else if (*p == '[') {
+			q = p + 1;
+			if (*q == '!' || *q == '^')
+				q++;
+			for (;;) {
+				if (*q == CTLESC)
+					q++;
+				if (*q == '/' || *q == '\0')
+					break;
+				if (*++q == ']') {
+					metaflag = 1;
+					break;
+				}
+			}
+		} else if (*p == '\0')
+			break;
+		else {
+			if (*p == CTLESC)
+				esc++;
+			if (p[esc] == '/') {
+				if (metaflag)
+					break;
+				start = p + esc + 1;
+			}
+		}
+	}
+	if (metaflag == 0) {	/* we've reached the end of the file name */
+		if (enddir != expdir)
+			metaflag++;
+		for (p = name ; ; p++) {
+			if (*p == CTLESC)
+				p++;
+			*enddir++ = *p;
+			if (*p == '\0')
+				break;
+			if (enddir == expdir_end)
+				return;
+		}
+		if (metaflag == 0 || lstat(expdir, &statb) >= 0)
+			appendarglist(arglist, stsavestr(expdir));
+		return;
+	}
+	endname = name + (p - name);
+	if (start != name) {
+		p = name;
+		while (p < start) {
+			if (*p == CTLESC)
+				p++;
+			*enddir++ = *p++;
+			if (enddir == expdir_end)
+				return;
+		}
+	}
+	if (enddir == expdir) {
+		p = ".";
+	} else if (enddir == expdir + 1 && *expdir == '/') {
+		p = "/";
+	} else {
+		p = expdir;
+		enddir[-1] = '\0';
+	}
+	if ((dirp = opendir(p)) == NULL)
+		return;
+	if (enddir != expdir)
+		enddir[-1] = '/';
+	if (*endname == 0) {
+		atend = 1;
+	} else {
+		atend = 0;
+		*endname = '\0';
+		endname += esc + 1;
+	}
+	matchdot = 0;
+	p = start;
+	if (*p == CTLESC)
+		p++;
+	if (*p == '.')
+		matchdot++;
+	while (! int_pending() && (dp = readdir(dirp)) != NULL) {
+		if (dp->d_name[0] == '.' && ! matchdot)
+			continue;
+		if (patmatch(start, dp->d_name)) {
+			namlen = dp->d_namlen;
+			if (enddir + namlen + 1 > expdir_end)
+				continue;
+			memcpy(enddir, dp->d_name, namlen + 1);
+			if (atend)
+				appendarglist(arglist, stsavestr(expdir));
+			else {
+				if (dp->d_type != DT_UNKNOWN &&
+				    dp->d_type != DT_DIR &&
+				    dp->d_type != DT_LNK)
+					continue;
+				if (enddir + namlen + 2 > expdir_end)
+					continue;
+				enddir[namlen] = '/';
+				enddir[namlen + 1] = '\0';
+				expmeta(enddir + namlen + 1, endname, arglist);
+			}
+		}
+	}
+	closedir(dirp);
+	if (! atend)
+		endname[-esc - 1] = esc ? CTLESC : '/';
+}
+
+
+static int
+expsortcmp(const void *p1, const void *p2)
+{
+	const char *s1 = *(const char * const *)p1;
+	const char *s2 = *(const char * const *)p2;
+
+	return (strcoll(s1, s2));
+}
+
+
+
+static wchar_t
+get_wc(const char **p)
+{
+	wchar_t c;
+	int chrlen;
+
+	chrlen = mbtowc(&c, *p, 4);
+	if (chrlen == 0)
+		return 0;
+	else if (chrlen == -1)
+		c = 0;
+	else
+		*p += chrlen;
+	return c;
+}
+
+
+/*
+ * See if a character matches a character class, starting at the first colon
+ * of "[:class:]".
+ * If a valid character class is recognized, a pointer to the next character
+ * after the final closing bracket is stored into *end, otherwise a null
+ * pointer is stored into *end.
+ */
+static int
+match_charclass(const char *p, wchar_t chr, const char **end)
+{
+	char name[20];
+	const char *nameend;
+	wctype_t cclass;
+
+	*end = NULL;
+	p++;
+	nameend = strstr(p, ":]");
+	if (nameend == NULL || (size_t)(nameend - p) >= sizeof(name) ||
+	    nameend == p)
+		return 0;
+	memcpy(name, p, nameend - p);
+	name[nameend - p] = '\0';
+	*end = nameend + 2;
+	cclass = wctype(name);
+	/* An unknown class matches nothing but is valid nevertheless. */
+	if (cclass == 0)
+		return 0;
+	return iswctype(chr, cclass);
+}
+
+
+/*
+ * Returns true if the pattern matches the string.
+ */
+
+static int
+patmatch(const char *pattern, const char *string)
+{
+	const char *p, *q, *end;
+	const char *bt_p, *bt_q;
+	char c;
+	wchar_t wc, wc2;
+
+	p = pattern;
+	q = string;
+	bt_p = NULL;
+	bt_q = NULL;
+	for (;;) {
+		switch (c = *p++) {
+		case '\0':
+			if (*q != '\0')
+				goto backtrack;
+			return 1;
+		case CTLESC:
+			if (*q++ != *p++)
+				goto backtrack;
+			break;
+		case '?':
+			if (*q == '\0')
+				return 0;
+			if (localeisutf8) {
+				wc = get_wc(&q);
+				/*
+				 * A '?' does not match invalid UTF-8 but a
+				 * '*' does, so backtrack.
+				 */
+				if (wc == 0)
+					goto backtrack;
+			} else
+				q++;
+			break;
+		case '*':
+			c = *p;
+			while (c == '*')
+				c = *++p;
+			/*
+			 * If the pattern ends here, we know the string
+			 * matches without needing to look at the rest of it.
+			 */
+			if (c == '\0')
+				return 1;
+			/*
+			 * First try the shortest match for the '*' that
+			 * could work. We can forget any earlier '*' since
+			 * there is no way having it match more characters
+			 * can help us, given that we are already here.
+			 */
+			bt_p = p;
+			bt_q = q;
+			break;
+		case '[': {
+			const char *savep, *saveq;
+			int invert, found;
+			wchar_t chr;
+
+			savep = p, saveq = q;
+			invert = 0;
+			if (*p == '!' || *p == '^') {
+				invert++;
+				p++;
+			}
+			found = 0;
+			if (*q == '\0')
+				return 0;
+			if (localeisutf8) {
+				chr = get_wc(&q);
+				if (chr == 0)
+					goto backtrack;
+			} else
+				chr = (unsigned char)*q++;
+			c = *p++;
+			do {
+				if (c == '\0') {
+					p = savep, q = saveq;
+					c = '[';
+					goto dft;
+				}
+				if (c == '[' && *p == ':') {
+					found |= match_charclass(p, chr, &end);
+					if (end != NULL) {
+						p = end;
+						continue;
+					}
+				}
+				if (c == CTLESC)
+					c = *p++;
+				if (localeisutf8 && c & 0x80) {
+					p--;
+					wc = get_wc(&p);
+					if (wc == 0) /* bad utf-8 */
+						return 0;
+				} else
+					wc = (unsigned char)c;
+				if (*p == '-' && p[1] != ']') {
+					p++;
+					if (*p == CTLESC)
+						p++;
+					if (localeisutf8) {
+						wc2 = get_wc(&p);
+						if (wc2 == 0) /* bad utf-8 */
+							return 0;
+					} else
+						wc2 = (unsigned char)*p++;
+					if (   collate_range_cmp(chr, wc) >= 0
+					    && collate_range_cmp(chr, wc2) <= 0
+					   )
+						found = 1;
+				} else {
+					if (chr == wc)
+						found = 1;
+				}
+			} while ((c = *p++) != ']');
+			if (found == invert)
+				goto backtrack;
+			break;
+		}
+dft:	        default:
+			if (*q == '\0')
+				return 0;
+			if (*q++ == c)
+				break;
+backtrack:
+			/*
+			 * If we have a mismatch (other than hitting the end
+			 * of the string), go back to the last '*' seen and
+			 * have it match one additional character.
+			 */
+			if (bt_p == NULL)
+				return 0;
+			if (*bt_q == '\0')
+				return 0;
+			bt_q++;
+			p = bt_p;
+			q = bt_q;
+			break;
+		}
+	}
+}
+
+
+
+/*
+ * Remove any CTLESC and CTLQUOTEMARK characters from a string.
+ */
+
+void
+rmescapes(char *str)
+{
+	char *p, *q;
+
+	p = str;
+	while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
+		if (*p++ == '\0')
+			return;
+	}
+	q = p;
+	while (*p) {
+		if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
+			p++;
+			continue;
+		}
+		if (*p == CTLESC)
+			p++;
+		*q++ = *p++;
+	}
+	*q = '\0';
+}
+
+
+
+/*
+ * See if a pattern matches in a case statement.
+ */
+
+int
+casematch(union node *pattern, const char *val)
+{
+	struct stackmark smark;
+	struct nodelist *argbackq;
+	int result;
+	char *p;
+
+	setstackmark(&smark);
+	argbackq = pattern->narg.backquote;
+	STARTSTACKSTR(expdest);
+	argstr(pattern->narg.text, &argbackq, EXP_TILDE | EXP_CASE, NULL);
+	STPUTC('\0', expdest);
+	p = grabstackstr(expdest);
+	result = patmatch(p, val);
+	popstackmark(&smark);
+	return result;
+}
+
+/*
+ * Our own itoa().
+ */
+
+static void
+cvtnum(int num, char *buf)
+{
+	char temp[32];
+	int neg = num < 0;
+	char *p = temp + 31;
+
+	temp[31] = '\0';
+
+	do {
+		*--p = num % 10 + '0';
+	} while ((num /= 10) != 0);
+
+	if (neg)
+		*--p = '-';
+
+	memcpy(buf, p, temp + 32 - p);
+}
+
+/*
+ * Do most of the work for wordexp(3).
+ */
+
+int
+wordexpcmd(int argc, char **argv)
+{
+	size_t len;
+	int i;
+
+	out1fmt("%08x", argc - 1);
+	for (i = 1, len = 0; i < argc; i++)
+		len += strlen(argv[i]);
+	out1fmt("%08x", (int)len);
+	for (i = 1; i < argc; i++)
+		outbin(argv[i], strlen(argv[i]) + 1, out1);
+        return (0);
+}
+
+/*
+ * Do most of the work for wordexp(3), new version.
+ */
+
+int
+freebsd_wordexpcmd(int argc __unused, char **argv __unused)
+{
+	struct arglist arglist;
+	union node *args, *n;
+	size_t len;
+	int ch;
+	int protected = 0;
+	int fd = -1;
+	int i;
+
+	while ((ch = nextopt("f:p")) != '\0') {
+		switch (ch) {
+		case 'f':
+			fd = number(shoptarg);
+			break;
+		case 'p':
+			protected = 1;
+			break;
+		}
+	}
+	if (*argptr != NULL)
+		error("wrong number of arguments");
+	if (fd < 0)
+		error("missing fd");
+	INTOFF;
+	setinputfd(fd, 1);
+	INTON;
+	args = parsewordexp();
+	popfile(); /* will also close fd */
+	if (protected)
+		for (n = args; n != NULL; n = n->narg.next) {
+			if (n->narg.backquote != NULL) {
+				outcslow('C', out1);
+				error("command substitution disabled");
+			}
+		}
+	outcslow(' ', out1);
+	emptyarglist(&arglist);
+	for (n = args; n != NULL; n = n->narg.next)
+		expandarg(n, &arglist, EXP_FULL | EXP_TILDE);
+	for (i = 0, len = 0; i < arglist.count; i++)
+		len += strlen(arglist.args[i]);
+	out1fmt("%016x %016zx", arglist.count, len);
+	for (i = 0; i < arglist.count; i++)
+		outbin(arglist.args[i], strlen(arglist.args[i]) + 1, out1);
+	return (0);
+}
diff --git a/bin/1sh/expand.h b/bin/1sh/expand.h
new file mode 100644
index 00000000..2bd9bbd9
--- /dev/null
+++ b/bin/1sh/expand.h
@@ -0,0 +1,62 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)expand.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/expand.h 314436 2017-02-28 23:42:47Z imp $
+ */
+
+struct arglist {
+	char **args;
+	int count;
+	int capacity;
+	char *smallarg[1];
+};
+
+/*
+ * expandarg() flags
+ */
+#define EXP_SPLIT	0x1	/* perform word splitting */
+#define EXP_TILDE	0x2	/* do normal tilde expansion */
+#define	EXP_VARTILDE	0x4	/* expand tildes in an assignment */
+#define EXP_CASE	0x10	/* keeps quotes around for CASE pattern */
+#define EXP_SPLIT_LIT	0x20	/* IFS split literal text ${v+-a b c} */
+#define EXP_LIT_QUOTED	0x40	/* for EXP_SPLIT_LIT, start off quoted */
+#define EXP_GLOB	0x80	/* perform file globbing */
+
+#define EXP_FULL	(EXP_SPLIT | EXP_GLOB)
+
+
+void emptyarglist(struct arglist *);
+void appendarglist(struct arglist *, char *);
+union node;
+void expandarg(union node *, struct arglist *, int);
+void rmescapes(char *);
+int casematch(union node *, const char *);
diff --git a/bin/1sh/histedit.c b/bin/1sh/histedit.c
new file mode 100644
index 00000000..e0bda06e
--- /dev/null
+++ b/bin/1sh/histedit.c
@@ -0,0 +1,558 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)histedit.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/histedit.c 345613 2019-03-27 21:53:44Z jilles $ */
+
+#include <sys/param.h>
+#include <limits.h>
+#include <paths.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+/*
+ * Editline and history functions (and glue).
+ */
+#include "shell.h"
+#include "parser.h"
+#include "var.h"
+#include "options.h"
+#include "main.h"
+#include "output.h"
+#include "mystring.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#include "error.h"
+#include "eval.h"
+#include "memalloc.h"
+#include "builtins.h"
+
+#define MAXHISTLOOPS	4	/* max recursions through fc */
+#define DEFEDITOR	"ed"	/* default editor *should* be $EDITOR */
+
+History *hist;	/* history cookie */
+EditLine *el;	/* editline cookie */
+int displayhist;
+static FILE *el_in, *el_out, *el_err;
+
+static void history_load(const char *hf);
+static void history_save(const char *hf);
+
+static char *fc_replace(const char *, char *, char *);
+static int not_fcnumber(const char *);
+static int str_to_event(const char *, int);
+
+/*
+ * Set history and editing status.  Called whenever the status may
+ * have changed (figures out what to do).
+ */
+void
+histedit(void)
+{
+
+#define editing (Eflag || Vflag)
+
+	if (iflag) {
+		if (!hist) {
+			/*
+			 * turn history on
+			 */
+			INTOFF;
+			hist = history_init();
+			INTON;
+
+			if (hist != NULL) {
+				sethistsize(histsizeval());
+				sethistfile(histfileval());
+			} else
+				out2fmt_flush("sh: can't initialize history\n");
+		}
+		if (editing && !el && isatty(0)) { /* && isatty(2) ??? */
+			/*
+			 * turn editing on
+			 */
+			char *term;
+
+			INTOFF;
+			if (el_in == NULL)
+				el_in = fdopen(0, "r");
+			if (el_err == NULL)
+				el_err = fdopen(1, "w");
+			if (el_out == NULL)
+				el_out = fdopen(2, "w");
+			if (el_in == NULL || el_err == NULL || el_out == NULL)
+				goto bad;
+			term = lookupvar("TERM");
+			if (term)
+				setenv("TERM", term, 1);
+			else
+				unsetenv("TERM");
+			el = el_init(arg0, el_in, el_out, el_err);
+			if (el != NULL) {
+				if (hist)
+					el_set(el, EL_HIST, history, hist);
+				el_set(el, EL_PROMPT, getprompt);
+				el_set(el, EL_RPROMPT, getrprompt);
+				el_set(el, EL_ADDFN, "sh-complete",
+				    "Filename completion",
+				    _el_fn_complete);
+			} else {
+bad:
+				out2fmt_flush("sh: can't initialize editing\n");
+			}
+			INTON;
+		} else if (!editing && el) {
+			INTOFF;
+			el_end(el);
+			el = NULL;
+			INTON;
+		}
+		if (el) {
+			el_source(el, NULL);
+			if (Vflag)
+				el_set(el, EL_EDITOR, "vi");
+			else if (Eflag)
+				el_set(el, EL_EDITOR, "emacs");
+			el_set(el, EL_BIND, "^I", "sh-complete", NULL);
+		}
+	} else {
+		INTOFF;
+		if (el) {	/* no editing if not interactive */
+			el_end(el);
+			el = NULL;
+		}
+		if (hist) {
+			if (*histfileval() != '\0')
+				history_save(histfileval());
+			history_end(hist);
+			hist = NULL;
+		}
+		INTON;
+	}
+}
+
+
+void
+sethistfile(const char *hf)
+{
+	if (hist != NULL && hf != NULL && *hf != '\0')
+		history_load(hf);
+}
+
+
+static void
+history_load(const char *hf)
+{
+	HistEvent he;
+
+	if (history(hist, &he, H_LOAD, hf) == -1)
+		warning("%s: %s", he.str, hf);
+}
+
+
+static void
+history_save(const char *hf)
+{
+	HistEvent he;
+
+	if (history(hist, &he, H_SAVE, hf) == -1)
+		warning("%s: %s", he.str, hf);
+}
+
+
+void
+sethistsize(const char *hs)
+{
+	int histsize;
+	HistEvent he;
+
+	if (hist != NULL) {
+		if (hs == NULL || !is_number(hs))
+			histsize = 100;
+		else
+			histsize = atoi(hs);
+		history(hist, &he, H_SETSIZE, histsize);
+		history(hist, &he, H_SETUNIQUE, 1);
+	}
+}
+
+void
+setterm(const char *term)
+{
+	if (rootshell && el != NULL && term != NULL)
+		el_set(el, EL_TERMINAL, term);
+}
+
+int
+histcmd(int argc, char **argv __unused)
+{
+	int ch;
+	const char *editor = NULL;
+	HistEvent he;
+	int lflg = 0, nflg = 0, rflg = 0, sflg = 0;
+	int i, retval;
+	const char *firststr, *laststr;
+	int first, last, direction;
+	char *pat = NULL, *repl = NULL;
+	static int active = 0;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	char editfilestr[PATH_MAX];
+	char *volatile editfile;
+	FILE *efp = NULL;
+	int oldhistnum;
+
+	if (hist == NULL)
+		error("history not active");
+
+	if (argc == 1)
+		error("missing history argument");
+
+	while (not_fcnumber(*argptr) && (ch = nextopt("e:lnrs")) != '\0')
+		switch ((char)ch) {
+		case 'e':
+			editor = shoptarg;
+			break;
+		case 'l':
+			lflg = 1;
+			break;
+		case 'n':
+			nflg = 1;
+			break;
+		case 'r':
+			rflg = 1;
+			break;
+		case 's':
+			sflg = 1;
+			break;
+		}
+
+	savehandler = handler;
+	/*
+	 * If executing...
+	 */
+	if (lflg == 0 || editor || sflg) {
+		lflg = 0;	/* ignore */
+		editfile = NULL;
+		/*
+		 * Catch interrupts to reset active counter and
+		 * cleanup temp files.
+		 */
+		if (setjmp(jmploc.loc)) {
+			active = 0;
+			if (editfile)
+				unlink(editfile);
+			handler = savehandler;
+			longjmp(handler->loc, 1);
+		}
+		handler = &jmploc;
+		if (++active > MAXHISTLOOPS) {
+			active = 0;
+			displayhist = 0;
+			error("called recursively too many times");
+		}
+		/*
+		 * Set editor.
+		 */
+		if (sflg == 0) {
+			if (editor == NULL &&
+			    (editor = bltinlookup("FCEDIT", 1)) == NULL &&
+			    (editor = bltinlookup("EDITOR", 1)) == NULL)
+				editor = DEFEDITOR;
+			if (editor[0] == '-' && editor[1] == '\0') {
+				sflg = 1;	/* no edit */
+				editor = NULL;
+			}
+		}
+	}
+
+	/*
+	 * If executing, parse [old=new] now
+	 */
+	if (lflg == 0 && *argptr != NULL &&
+	     ((repl = strchr(*argptr, '=')) != NULL)) {
+		pat = *argptr;
+		*repl++ = '\0';
+		argptr++;
+	}
+	/*
+	 * determine [first] and [last]
+	 */
+	if (*argptr == NULL) {
+		firststr = lflg ? "-16" : "-1";
+		laststr = "-1";
+	} else if (argptr[1] == NULL) {
+		firststr = argptr[0];
+		laststr = lflg ? "-1" : argptr[0];
+	} else if (argptr[2] == NULL) {
+		firststr = argptr[0];
+		laststr = argptr[1];
+	} else
+		error("too many arguments");
+	/*
+	 * Turn into event numbers.
+	 */
+	first = str_to_event(firststr, 0);
+	last = str_to_event(laststr, 1);
+
+	if (rflg) {
+		i = last;
+		last = first;
+		first = i;
+	}
+	/*
+	 * XXX - this should not depend on the event numbers
+	 * always increasing.  Add sequence numbers or offset
+	 * to the history element in next (diskbased) release.
+	 */
+	direction = first < last ? H_PREV : H_NEXT;
+
+	/*
+	 * If editing, grab a temp file.
+	 */
+	if (editor) {
+		int fd;
+		INTOFF;		/* easier */
+		sprintf(editfilestr, "%s/_shXXXXXX", _PATH_TMP);
+		if ((fd = mkstemp(editfilestr)) < 0)
+			error("can't create temporary file %s", editfile);
+		editfile = editfilestr;
+		if ((efp = fdopen(fd, "w")) == NULL) {
+			close(fd);
+			error("Out of space");
+		}
+	}
+
+	/*
+	 * Loop through selected history events.  If listing or executing,
+	 * do it now.  Otherwise, put into temp file and call the editor
+	 * after.
+	 *
+	 * The history interface needs rethinking, as the following
+	 * convolutions will demonstrate.
+	 */
+	history(hist, &he, H_FIRST);
+	retval = history(hist, &he, H_NEXT_EVENT, first);
+	for (;retval != -1; retval = history(hist, &he, direction)) {
+		if (lflg) {
+			if (!nflg)
+				out1fmt("%5d ", he.num);
+			out1str(he.str);
+		} else {
+			const char *s = pat ?
+			   fc_replace(he.str, pat, repl) : he.str;
+
+			if (sflg) {
+				if (displayhist) {
+					out2str(s);
+					flushout(out2);
+				}
+				evalstring(s, 0);
+				if (displayhist && hist) {
+					/*
+					 *  XXX what about recursive and
+					 *  relative histnums.
+					 */
+					oldhistnum = he.num;
+					history(hist, &he, H_ENTER, s);
+					/*
+					 * XXX H_ENTER moves the internal
+					 * cursor, set it back to the current
+					 * entry.
+					 */
+					history(hist, &he,
+					    H_NEXT_EVENT, oldhistnum);
+				}
+			} else
+				fputs(s, efp);
+		}
+		/*
+		 * At end?  (if we were to lose last, we'd sure be
+		 * messed up).
+		 */
+		if (he.num == last)
+			break;
+	}
+	if (editor) {
+		char *editcmd;
+
+		fclose(efp);
+		INTON;
+		editcmd = stalloc(strlen(editor) + strlen(editfile) + 2);
+		sprintf(editcmd, "%s %s", editor, editfile);
+		evalstring(editcmd, 0);	/* XXX - should use no JC command */
+		readcmdfile(editfile);	/* XXX - should read back - quick tst */
+		unlink(editfile);
+	}
+
+	if (lflg == 0 && active > 0)
+		--active;
+	if (displayhist)
+		displayhist = 0;
+	handler = savehandler;
+	return 0;
+}
+
+static char *
+fc_replace(const char *s, char *p, char *r)
+{
+	char *dest;
+	int plen = strlen(p);
+
+	STARTSTACKSTR(dest);
+	while (*s) {
+		if (*s == *p && strncmp(s, p, plen) == 0) {
+			STPUTS(r, dest);
+			s += plen;
+			*p = '\0';	/* so no more matches */
+		} else
+			STPUTC(*s++, dest);
+	}
+	STPUTC('\0', dest);
+	dest = grabstackstr(dest);
+
+	return (dest);
+}
+
+static int
+not_fcnumber(const char *s)
+{
+	if (s == NULL)
+		return (0);
+	if (*s == '-')
+		s++;
+	return (!is_number(s));
+}
+
+static int
+str_to_event(const char *str, int last)
+{
+	HistEvent he;
+	const char *s = str;
+	int relative = 0;
+	int i, retval;
+
+	retval = history(hist, &he, H_FIRST);
+	switch (*s) {
+	case '-':
+		relative = 1;
+		/*FALLTHROUGH*/
+	case '+':
+		s++;
+	}
+	if (is_number(s)) {
+		i = atoi(s);
+		if (relative) {
+			while (retval != -1 && i--) {
+				retval = history(hist, &he, H_NEXT);
+			}
+			if (retval == -1)
+				retval = history(hist, &he, H_LAST);
+		} else {
+			retval = history(hist, &he, H_NEXT_EVENT, i);
+			if (retval == -1) {
+				/*
+				 * the notion of first and last is
+				 * backwards to that of the history package
+				 */
+				retval = history(hist, &he, last ? H_FIRST : H_LAST);
+			}
+		}
+		if (retval == -1)
+			error("history number %s not found (internal error)",
+			       str);
+	} else {
+		/*
+		 * pattern
+		 */
+		retval = history(hist, &he, H_PREV_STR, str);
+		if (retval == -1)
+			error("history pattern not found: %s", str);
+	}
+	return (he.num);
+}
+
+int
+bindcmd(int argc, char **argv)
+{
+	int ret;
+	FILE *old;
+	FILE *out;
+
+	if (el == NULL)
+		error("line editing is disabled");
+
+	INTOFF;
+
+	out = out1fp();
+	if (out == NULL)
+		error("Out of space");
+
+	el_get(el, EL_GETFP, 1, &old);
+	el_set(el, EL_SETFP, 1, out);
+
+	ret = el_parse(el, argc, (const char **)(argv));
+
+	el_set(el, EL_SETFP, 1, old);
+
+	fclose(out);
+
+	INTON;
+
+	return ret;
+}
+
+#else
+#include "error.h"
+
+int
+histcmd(int argc, char **argv)
+{
+
+	error("not compiled with history support");
+	/*NOTREACHED*/
+	return (0);
+}
+
+int
+bindcmd(int argc, char **argv)
+{
+
+	error("not compiled with line editing support");
+	return (0);
+}
+#endif
diff --git a/bin/1sh/input.c b/bin/1sh/input.c
new file mode 100644
index 00000000..37f689a5
--- /dev/null
+++ b/bin/1sh/input.c
@@ -0,0 +1,520 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/input.c 314436 2017-02-28 23:42:47Z imp $ */
+
+#include <stdio.h>	/* defines BUFSIZ */
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * This file implements the input routines used by the parser.
+ */
+
+#include "shell.h"
+#include "redir.h"
+#include "syntax.h"
+#include "input.h"
+#include "output.h"
+#include "options.h"
+#include "memalloc.h"
+#include "error.h"
+#include "alias.h"
+#include "parser.h"
+#include "myhistedit.h"
+#include "trap.h"
+
+#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
+
+struct strpush {
+	struct strpush *prev;	/* preceding string on stack */
+	const char *prevstring;
+	int prevnleft;
+	int prevlleft;
+	struct alias *ap;	/* if push was associated with an alias */
+};
+
+/*
+ * The parsefile structure pointed to by the global variable parsefile
+ * contains information about the current file being read.
+ */
+
+struct parsefile {
+	struct parsefile *prev;	/* preceding file on stack */
+	int linno;		/* current line */
+	int fd;			/* file descriptor (or -1 if string) */
+	int nleft;		/* number of chars left in this line */
+	int lleft;		/* number of lines left in this buffer */
+	const char *nextc;	/* next char in buffer */
+	char *buf;		/* input buffer */
+	struct strpush *strpush; /* for pushing strings at this level */
+	struct strpush basestrpush; /* so pushing one is fast */
+};
+
+
+int plinno = 1;			/* input line number */
+int parsenleft;			/* copy of parsefile->nleft */
+static int parselleft;		/* copy of parsefile->lleft */
+const char *parsenextc;		/* copy of parsefile->nextc */
+static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
+static struct parsefile basepf = {	/* top level input file */
+	.nextc = basebuf,
+	.buf = basebuf
+};
+static struct parsefile *parsefile = &basepf;	/* current input file */
+int whichprompt;		/* 1 == PS1, 2 == PS2 */
+
+EditLine *el;			/* cookie for editline package */
+
+static void pushfile(void);
+static int preadfd(void);
+static void popstring(void);
+
+void
+resetinput(void)
+{
+	popallfiles();
+	parselleft = parsenleft = 0;	/* clear input buffer */
+}
+
+
+
+/*
+ * Read a character from the script, returning PEOF on end of file.
+ * Nul characters in the input are silently discarded.
+ */
+
+int
+pgetc(void)
+{
+	return pgetc_macro();
+}
+
+
+static int
+preadfd(void)
+{
+	int nr;
+	parsenextc = parsefile->buf;
+
+retry:
+#ifndef NO_HISTORY
+	if (parsefile->fd == 0 && el) {
+		static const char *rl_cp;
+		static int el_len;
+
+		if (rl_cp == NULL) {
+			el_resize(el);
+			rl_cp = el_gets(el, &el_len);
+		}
+		if (rl_cp == NULL)
+			nr = el_len == 0 ? 0 : -1;
+		else {
+			nr = el_len;
+			if (nr > BUFSIZ)
+				nr = BUFSIZ;
+			memcpy(parsefile->buf, rl_cp, nr);
+			if (nr != el_len) {
+				el_len -= nr;
+				rl_cp += nr;
+			} else
+				rl_cp = NULL;
+		}
+	} else
+#endif
+		nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
+
+	if (nr <= 0) {
+                if (nr < 0) {
+                        if (errno == EINTR)
+                                goto retry;
+                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
+                                int flags = fcntl(0, F_GETFL, 0);
+                                if (flags >= 0 && flags & O_NONBLOCK) {
+                                        flags &=~ O_NONBLOCK;
+                                        if (fcntl(0, F_SETFL, flags) >= 0) {
+						out2fmt_flush("sh: turning off NDELAY mode\n");
+                                                goto retry;
+                                        }
+                                }
+                        }
+                }
+                nr = -1;
+	}
+	return nr;
+}
+
+/*
+ * Refill the input buffer and return the next input character:
+ *
+ * 1) If a string was pushed back on the input, pop it;
+ * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
+ *    from a string so we can't refill the buffer, return EOF.
+ * 3) If there is more in this buffer, use it else call read to fill it.
+ * 4) Process input up to the next newline, deleting nul characters.
+ */
+
+int
+preadbuffer(void)
+{
+	char *p, *q, *r, *end;
+	char savec;
+
+	while (parsefile->strpush) {
+		/*
+		 * Add a space to the end of an alias to ensure that the
+		 * alias remains in use while parsing its last word.
+		 * This avoids alias recursions.
+		 */
+		if (parsenleft == -1 && parsefile->strpush->ap != NULL)
+			return ' ';
+		popstring();
+		if (--parsenleft >= 0)
+			return (*parsenextc++);
+	}
+	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
+		return PEOF;
+
+again:
+	if (parselleft <= 0) {
+		if ((parselleft = preadfd()) == -1) {
+			parselleft = parsenleft = EOF_NLEFT;
+			return PEOF;
+		}
+	}
+
+	p = parsefile->buf + (parsenextc - parsefile->buf);
+	end = p + parselleft;
+	*end = '\0';
+	q = strchr(p, '\n');
+	if (!q) q = strchr(p, '\0');
+	if (q != end && *q == '\0') {
+		/* delete nul characters */
+		for (r = q; q != end; q++) {
+			if (*q != '\0')
+				*r++ = *q;
+		}
+		parselleft -= end - r;
+		if (parselleft == 0)
+			goto again;
+		end = p + parselleft;
+		*end = '\0';
+		q = strchr(p, '\n');
+		if (!q) q = strchr(p, '\0');
+	}
+	if (q == end) {
+		parsenleft = parselleft;
+		parselleft = 0;
+	} else /* *q == '\n' */ {
+		q++;
+		parsenleft = q - parsenextc;
+		parselleft -= parsenleft;
+	}
+	parsenleft--;
+
+	savec = *q;
+	*q = '\0';
+
+#ifndef NO_HISTORY
+	if (parsefile->fd == 0 && hist &&
+	    parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
+		HistEvent he;
+		INTOFF;
+		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
+		    parsenextc);
+		INTON;
+	}
+#endif
+
+	if (vflag) {
+		out2str(parsenextc);
+		flushout(out2);
+	}
+
+	*q = savec;
+
+	return *parsenextc++;
+}
+
+/*
+ * Returns if we are certain we are at EOF. Does not cause any more input
+ * to be read from the outside world.
+ */
+
+int
+preadateof(void)
+{
+	if (parsenleft > 0)
+		return 0;
+	if (parsefile->strpush)
+		return 0;
+	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
+		return 1;
+	return 0;
+}
+
+/*
+ * Undo the last call to pgetc.  Only one character may be pushed back.
+ * PEOF may be pushed back.
+ */
+
+void
+pungetc(void)
+{
+	parsenleft++;
+	parsenextc--;
+}
+
+/*
+ * Push a string back onto the input at this current parsefile level.
+ * We handle aliases this way.
+ */
+void
+pushstring(const char *s, int len, struct alias *ap)
+{
+	struct strpush *sp;
+
+	INTOFF;
+/*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
+	if (parsefile->strpush) {
+		sp = ckmalloc(sizeof (struct strpush));
+		sp->prev = parsefile->strpush;
+		parsefile->strpush = sp;
+	} else
+		sp = parsefile->strpush = &(parsefile->basestrpush);
+	sp->prevstring = parsenextc;
+	sp->prevnleft = parsenleft;
+	sp->prevlleft = parselleft;
+	sp->ap = ap;
+	if (ap)
+		ap->flag |= ALIASINUSE;
+	parsenextc = s;
+	parsenleft = len;
+	INTON;
+}
+
+static void
+popstring(void)
+{
+	struct strpush *sp = parsefile->strpush;
+
+	INTOFF;
+	if (sp->ap) {
+		if (parsenextc != sp->ap->val &&
+		    (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
+			forcealias();
+		sp->ap->flag &= ~ALIASINUSE;
+	}
+	parsenextc = sp->prevstring;
+	parsenleft = sp->prevnleft;
+	parselleft = sp->prevlleft;
+/*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
+	parsefile->strpush = sp->prev;
+	if (sp != &(parsefile->basestrpush))
+		ckfree(sp);
+	INTON;
+}
+
+/*
+ * Set the input to take input from a file.  If push is set, push the
+ * old input onto the stack first.
+ */
+
+void
+setinputfile(const char *fname, int push)
+{
+	int fd;
+	int fd2;
+
+	INTOFF;
+	if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0)
+		error("cannot open %s: %s", fname, strerror(errno));
+	if (fd < 10) {
+		fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10);
+		close(fd);
+		if (fd2 < 0)
+			error("Out of file descriptors");
+		fd = fd2;
+	}
+	setinputfd(fd, push);
+	INTON;
+}
+
+
+/*
+ * Like setinputfile, but takes an open file descriptor (which should have
+ * its FD_CLOEXEC flag already set).  Call this with interrupts off.
+ */
+
+void
+setinputfd(int fd, int push)
+{
+	if (push) {
+		pushfile();
+		parsefile->buf = ckmalloc(BUFSIZ + 1);
+	}
+	if (parsefile->fd > 0)
+		close(parsefile->fd);
+	parsefile->fd = fd;
+	if (parsefile->buf == NULL)
+		parsefile->buf = ckmalloc(BUFSIZ + 1);
+	parselleft = parsenleft = 0;
+	plinno = 1;
+}
+
+
+/*
+ * Like setinputfile, but takes input from a string.
+ */
+
+void
+setinputstring(const char *string, int push)
+{
+	INTOFF;
+	if (push)
+		pushfile();
+	parsenextc = string;
+	parselleft = parsenleft = strlen(string);
+	parsefile->buf = NULL;
+	plinno = 1;
+	INTON;
+}
+
+
+
+/*
+ * To handle the "." command, a stack of input files is used.  Pushfile
+ * adds a new entry to the stack and popfile restores the previous level.
+ */
+
+static void
+pushfile(void)
+{
+	struct parsefile *pf;
+
+	parsefile->nleft = parsenleft;
+	parsefile->lleft = parselleft;
+	parsefile->nextc = parsenextc;
+	parsefile->linno = plinno;
+	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
+	pf->prev = parsefile;
+	pf->fd = -1;
+	pf->strpush = NULL;
+	pf->basestrpush.prev = NULL;
+	parsefile = pf;
+}
+
+
+void
+popfile(void)
+{
+	struct parsefile *pf = parsefile;
+
+	INTOFF;
+	if (pf->fd >= 0)
+		close(pf->fd);
+	if (pf->buf)
+		ckfree(pf->buf);
+	while (pf->strpush)
+		popstring();
+	parsefile = pf->prev;
+	ckfree(pf);
+	parsenleft = parsefile->nleft;
+	parselleft = parsefile->lleft;
+	parsenextc = parsefile->nextc;
+	plinno = parsefile->linno;
+	INTON;
+}
+
+
+/*
+ * Return current file (to go back to it later using popfilesupto()).
+ */
+
+struct parsefile *
+getcurrentfile(void)
+{
+	return parsefile;
+}
+
+
+/*
+ * Pop files until the given file is on top again. Useful for regular
+ * builtins that read shell commands from files or strings.
+ * If the given file is not an active file, an error is raised.
+ */
+
+void
+popfilesupto(struct parsefile *file)
+{
+	while (parsefile != file && parsefile != &basepf)
+		popfile();
+	if (parsefile != file)
+		error("popfilesupto() misused");
+}
+
+/*
+ * Return to top level.
+ */
+
+void
+popallfiles(void)
+{
+	while (parsefile != &basepf)
+		popfile();
+}
+
+
+
+/*
+ * Close the file(s) that the shell is reading commands from.  Called
+ * after a fork is done.
+ */
+
+void
+closescript(void)
+{
+	popallfiles();
+	if (parsefile->fd > 0) {
+		close(parsefile->fd);
+		parsefile->fd = 0;
+	}
+}
diff --git a/bin/1sh/input.h b/bin/1sh/input.h
new file mode 100644
index 00000000..1d0047cc
--- /dev/null
+++ b/bin/1sh/input.h
@@ -0,0 +1,65 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)input.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/input.h 314436 2017-02-28 23:42:47Z imp $
+ */
+
+/* PEOF (the end of file marker) is defined in syntax.h */
+
+/*
+ * The input line number.  Input.c just defines this variable, and saves
+ * and restores it when files are pushed and popped.  The user of this
+ * package must set its value.
+ */
+extern int plinno;
+extern int parsenleft;		/* number of characters left in input buffer */
+extern const char *parsenextc;	/* next character in input buffer */
+
+struct alias;
+struct parsefile;
+
+void resetinput(void);
+int pgetc(void);
+int preadbuffer(void);
+int preadateof(void);
+void pungetc(void);
+void pushstring(const char *, int, struct alias *);
+void setinputfile(const char *, int);
+void setinputfd(int, int);
+void setinputstring(const char *, int);
+void popfile(void);
+struct parsefile *getcurrentfile(void);
+void popfilesupto(struct parsefile *);
+void popallfiles(void);
+void closescript(void);
+
+#define pgetc_macro()	(--parsenleft >= 0? *parsenextc++ : preadbuffer())
diff --git a/bin/1sh/jobs.c b/bin/1sh/jobs.c
new file mode 100644
index 00000000..492251e0
--- /dev/null
+++ b/bin/1sh/jobs.c
@@ -0,0 +1,1569 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)jobs.c	8.5 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/jobs.c 345487 2019-03-24 22:10:26Z jilles $ */
+
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "shell.h"
+#if JOBS
+#include <termios.h>
+#undef CEOF			/* syntax.h redefines this */
+#endif
+#include "redir.h"
+#include "exec.h"
+#include "show.h"
+#include "main.h"
+#include "parser.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "options.h"
+#include "trap.h"
+#include "syntax.h"
+#include "input.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "var.h"
+#include "builtins.h"
+
+
+/*
+ * A job structure contains information about a job.  A job is either a
+ * single process or a set of processes contained in a pipeline.  In the
+ * latter case, pidlist will be non-NULL, and will point to a -1 terminated
+ * array of pids.
+ */
+
+struct procstat {
+	pid_t pid;		/* process id */
+	int status;		/* status flags (defined above) */
+	char *cmd;		/* text of command being run */
+};
+
+
+/* states */
+#define JOBSTOPPED 1		/* all procs are stopped */
+#define JOBDONE 2		/* all procs are completed */
+
+
+struct job {
+	struct procstat ps0;	/* status of process */
+	struct procstat *ps;	/* status or processes when more than one */
+	short nprocs;		/* number of processes */
+	pid_t pgrp;		/* process group of this job */
+	char state;		/* true if job is finished */
+	char used;		/* true if this entry is in used */
+	char changed;		/* true if status has changed */
+	char foreground;	/* true if running in the foreground */
+	char remembered;	/* true if $! referenced */
+	char pipefail;		/* pass any non-zero status */
+#if JOBS
+	char jobctl;		/* job running under job control */
+	struct job *next;	/* job used after this one */
+#endif
+};
+
+
+static struct job *jobtab;	/* array of jobs */
+static int njobs;		/* size of array */
+static pid_t backgndpid = -1;	/* pid of last background process */
+static struct job *bgjob = NULL; /* last background process */
+#if JOBS
+static struct job *jobmru;	/* most recently used job list */
+static pid_t initialpgrp;	/* pgrp of shell on invocation */
+#endif
+static int ttyfd = -1;
+
+/* mode flags for dowait */
+#define DOWAIT_BLOCK	0x1 /* wait until a child exits */
+#define DOWAIT_SIG	0x2 /* if DOWAIT_BLOCK, abort on signal */
+#define DOWAIT_SIG_TRAP	0x4 /* if DOWAIT_SIG, abort on trapped signal only */
+
+#if JOBS
+static void restartjob(struct job *);
+#endif
+static void freejob(struct job *);
+static int waitcmdloop(struct job *);
+static struct job *getjob_nonotfound(const char *);
+static struct job *getjob(const char *);
+pid_t killjob(const char *, int);
+static pid_t dowait(int, struct job *);
+static void checkzombies(void);
+static void cmdtxt(union node *);
+static void cmdputs(const char *);
+#if JOBS
+static void setcurjob(struct job *);
+static void deljob(struct job *);
+static struct job *getcurjob(struct job *);
+#endif
+static int getjobstatus(const struct job *);
+static void printjobcmd(struct job *);
+static void showjob(struct job *, int);
+
+
+/*
+ * Turn job control on and off.
+ */
+
+static int jobctl;
+
+#if JOBS
+static void
+jobctl_notty(void)
+{
+	if (ttyfd >= 0) {
+		close(ttyfd);
+		ttyfd = -1;
+	}
+	if (!iflag) {
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+		jobctl = 1;
+		return;
+	}
+	out2fmt_flush("sh: can't access tty; job control turned off\n");
+	mflag = 0;
+}
+
+void
+setjobctl(int on)
+{
+	int i;
+
+	if (on == jobctl || rootshell == 0)
+		return;
+	if (on) {
+		if (ttyfd != -1)
+			close(ttyfd);
+		if ((ttyfd = open(_PATH_TTY, O_RDWR | O_CLOEXEC)) < 0) {
+			i = 0;
+			while (i <= 2 && !isatty(i))
+				i++;
+			if (i > 2 ||
+			    (ttyfd = fcntl(i, F_DUPFD_CLOEXEC, 10)) < 0) {
+				jobctl_notty();
+				return;
+			}
+		}
+		if (ttyfd < 10) {
+			/*
+			 * Keep our TTY file descriptor out of the way of
+			 * the user's redirections.
+			 */
+			if ((i = fcntl(ttyfd, F_DUPFD_CLOEXEC, 10)) < 0) {
+				jobctl_notty();
+				return;
+			}
+			close(ttyfd);
+			ttyfd = i;
+		}
+		do { /* while we are in the background */
+			initialpgrp = tcgetpgrp(ttyfd);
+			if (initialpgrp < 0) {
+				jobctl_notty();
+				return;
+			}
+			if (initialpgrp != getpgrp()) {
+				if (!iflag) {
+					initialpgrp = -1;
+					jobctl_notty();
+					return;
+				}
+				kill(0, SIGTTIN);
+				continue;
+			}
+		} while (0);
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+		setpgid(0, rootpid);
+		tcsetpgrp(ttyfd, rootpid);
+	} else { /* turning job control off */
+		setpgid(0, initialpgrp);
+		if (ttyfd >= 0) {
+			tcsetpgrp(ttyfd, initialpgrp);
+			close(ttyfd);
+			ttyfd = -1;
+		}
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+	}
+	jobctl = on;
+}
+#endif
+
+
+#if JOBS
+int
+fgcmd(int argc __unused, char **argv __unused)
+{
+	struct job *jp;
+	pid_t pgrp;
+	int status;
+
+	nextopt("");
+	jp = getjob(*argptr);
+	if (jp->jobctl == 0)
+		error("job not created under job control");
+	printjobcmd(jp);
+	flushout(&output);
+	pgrp = jp->ps[0].pid;
+	if (ttyfd >= 0)
+		tcsetpgrp(ttyfd, pgrp);
+	restartjob(jp);
+	jp->foreground = 1;
+	INTOFF;
+	status = waitforjob(jp, (int *)NULL);
+	INTON;
+	return status;
+}
+
+
+int
+bgcmd(int argc __unused, char **argv __unused)
+{
+	struct job *jp;
+
+	nextopt("");
+	do {
+		jp = getjob(*argptr);
+		if (jp->jobctl == 0)
+			error("job not created under job control");
+		if (jp->state == JOBDONE)
+			continue;
+		restartjob(jp);
+		jp->foreground = 0;
+		out1fmt("[%td] ", jp - jobtab + 1);
+		printjobcmd(jp);
+	} while (*argptr != NULL && *++argptr != NULL);
+	return 0;
+}
+
+
+static void
+restartjob(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	if (jp->state == JOBDONE)
+		return;
+	setcurjob(jp);
+	INTOFF;
+	kill(-jp->ps[0].pid, SIGCONT);
+	for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
+		if (WIFSTOPPED(ps->status)) {
+			ps->status = -1;
+			jp->state = 0;
+		}
+	}
+	INTON;
+}
+#endif
+
+
+int
+jobscmd(int argc __unused, char *argv[] __unused)
+{
+	char *id;
+	int ch, mode;
+
+	mode = SHOWJOBS_DEFAULT;
+	while ((ch = nextopt("lps")) != '\0') {
+		switch (ch) {
+		case 'l':
+			mode = SHOWJOBS_VERBOSE;
+			break;
+		case 'p':
+			mode = SHOWJOBS_PGIDS;
+			break;
+		case 's':
+			mode = SHOWJOBS_PIDS;
+			break;
+		}
+	}
+
+	if (*argptr == NULL)
+		showjobs(0, mode);
+	else
+		while ((id = *argptr++) != NULL)
+			showjob(getjob(id), mode);
+
+	return (0);
+}
+
+static int getjobstatus(const struct job *jp)
+{
+	int i, status;
+
+	if (!jp->pipefail)
+		return (jp->ps[jp->nprocs - 1].status);
+	for (i = jp->nprocs - 1; i >= 0; i--) {
+		status = jp->ps[i].status;
+		if (status != 0)
+			return (status);
+	}
+	return (0);
+}
+
+static void
+printjobcmd(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
+		out1str(ps->cmd);
+		if (i > 0)
+			out1str(" | ");
+	}
+	out1c('\n');
+}
+
+static void
+showjob(struct job *jp, int mode)
+{
+	char s[64];
+	char statebuf[16];
+	const char *statestr, *coredump;
+	struct procstat *ps;
+	struct job *j;
+	int col, curr, i, jobno, prev, procno, status;
+	char c;
+
+	procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
+	jobno = jp - jobtab + 1;
+	curr = prev = 0;
+#if JOBS
+	if ((j = getcurjob(NULL)) != NULL) {
+		curr = j - jobtab + 1;
+		if ((j = getcurjob(j)) != NULL)
+			prev = j - jobtab + 1;
+	}
+#endif
+	coredump = "";
+	status = getjobstatus(jp);
+	if (jp->state == 0) {
+		statestr = "Running";
+#if JOBS
+	} else if (jp->state == JOBSTOPPED) {
+		ps = jp->ps + jp->nprocs - 1;
+		while (!WIFSTOPPED(ps->status) && ps > jp->ps)
+			ps--;
+		if (WIFSTOPPED(ps->status))
+			i = WSTOPSIG(ps->status);
+		else
+			i = -1;
+		statestr = strsignal(i);
+		if (statestr == NULL)
+			statestr = "Suspended";
+#endif
+	} else if (WIFEXITED(status)) {
+		if (WEXITSTATUS(status) == 0)
+			statestr = "Done";
+		else {
+			fmtstr(statebuf, sizeof(statebuf), "Done(%d)",
+			    WEXITSTATUS(status));
+			statestr = statebuf;
+		}
+	} else {
+		i = WTERMSIG(status);
+		statestr = strsignal(i);
+		if (statestr == NULL)
+			statestr = "Unknown signal";
+		if (WCOREDUMP(status))
+			coredump = " (core dumped)";
+	}
+
+	for (ps = jp->ps ; procno > 0 ; ps++, procno--) { /* for each process */
+		if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
+			out1fmt("%d\n", (int)ps->pid);
+			continue;
+		}
+		if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
+			continue;
+		if (jobno == curr && ps == jp->ps)
+			c = '+';
+		else if (jobno == prev && ps == jp->ps)
+			c = '-';
+		else
+			c = ' ';
+		if (ps == jp->ps)
+			fmtstr(s, 64, "[%d] %c ", jobno, c);
+		else
+			fmtstr(s, 64, "    %c ", c);
+		out1str(s);
+		col = strlen(s);
+		if (mode == SHOWJOBS_VERBOSE) {
+			fmtstr(s, 64, "%d ", (int)ps->pid);
+			out1str(s);
+			col += strlen(s);
+		}
+		if (ps == jp->ps) {
+			out1str(statestr);
+			out1str(coredump);
+			col += strlen(statestr) + strlen(coredump);
+		}
+		do {
+			out1c(' ');
+			col++;
+		} while (col < 30);
+		if (mode == SHOWJOBS_VERBOSE) {
+			out1str(ps->cmd);
+			out1c('\n');
+		} else
+			printjobcmd(jp);
+	}
+}
+
+/*
+ * Print a list of jobs.  If "change" is nonzero, only print jobs whose
+ * statuses have changed since the last call to showjobs.
+ *
+ * If the shell is interrupted in the process of creating a job, the
+ * result may be a job structure containing zero processes.  Such structures
+ * will be freed here.
+ */
+
+void
+showjobs(int change, int mode)
+{
+	int jobno;
+	struct job *jp;
+
+	TRACE(("showjobs(%d) called\n", change));
+	checkzombies();
+	for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
+		if (! jp->used)
+			continue;
+		if (jp->nprocs == 0) {
+			freejob(jp);
+			continue;
+		}
+		if (change && ! jp->changed)
+			continue;
+		showjob(jp, mode);
+		if (mode == SHOWJOBS_DEFAULT || mode == SHOWJOBS_VERBOSE) {
+			jp->changed = 0;
+			/* Hack: discard jobs for which $! has not been
+			 * referenced in interactive mode when they terminate.
+			 */
+			if (jp->state == JOBDONE && !jp->remembered &&
+					(iflag || jp != bgjob)) {
+				freejob(jp);
+			}
+		}
+	}
+}
+
+
+/*
+ * Mark a job structure as unused.
+ */
+
+static void
+freejob(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	INTOFF;
+	if (bgjob == jp)
+		bgjob = NULL;
+	for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
+		if (ps->cmd != nullstr)
+			ckfree(ps->cmd);
+	}
+	if (jp->ps != &jp->ps0)
+		ckfree(jp->ps);
+	jp->used = 0;
+#if JOBS
+	deljob(jp);
+#endif
+	INTON;
+}
+
+
+
+int
+waitcmd(int argc __unused, char **argv __unused)
+{
+	struct job *job;
+	int retval;
+
+	nextopt("");
+	if (*argptr == NULL)
+		return (waitcmdloop(NULL));
+
+	do {
+		job = getjob_nonotfound(*argptr);
+		if (job == NULL)
+			retval = 127;
+		else
+			retval = waitcmdloop(job);
+		argptr++;
+	} while (*argptr != NULL);
+
+	return (retval);
+}
+
+static int
+waitcmdloop(struct job *job)
+{
+	int status, retval, sig;
+	struct job *jp;
+
+	/*
+	 * Loop until a process is terminated or stopped, or a SIGINT is
+	 * received.
+	 */
+
+	do {
+		if (job != NULL) {
+			if (job->state == JOBDONE) {
+				status = getjobstatus(job);
+				if (WIFEXITED(status))
+					retval = WEXITSTATUS(status);
+				else
+					retval = WTERMSIG(status) + 128;
+				if (! iflag || ! job->changed)
+					freejob(job);
+				else {
+					job->remembered = 0;
+					if (job == bgjob)
+						bgjob = NULL;
+				}
+				return retval;
+			}
+		} else {
+			for (jp = jobtab ; jp < jobtab + njobs; jp++)
+				if (jp->used && jp->state == JOBDONE) {
+					if (! iflag || ! jp->changed)
+						freejob(jp);
+					else {
+						jp->remembered = 0;
+						if (jp == bgjob)
+							bgjob = NULL;
+					}
+				}
+			for (jp = jobtab ; ; jp++) {
+				if (jp >= jobtab + njobs) {	/* no running procs */
+					return 0;
+				}
+				if (jp->used && jp->state == 0)
+					break;
+			}
+		}
+	} while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
+
+	sig = pendingsig_waitcmd;
+	pendingsig_waitcmd = 0;
+	return sig + 128;
+}
+
+
+
+int
+jobidcmd(int argc __unused, char **argv __unused)
+{
+	struct job *jp;
+	int i;
+
+	nextopt("");
+	jp = getjob(*argptr);
+	for (i = 0 ; i < jp->nprocs ; ) {
+		out1fmt("%d", (int)jp->ps[i].pid);
+		out1c(++i < jp->nprocs? ' ' : '\n');
+	}
+	return 0;
+}
+
+
+
+/*
+ * Convert a job name to a job structure.
+ */
+
+static struct job *
+getjob_nonotfound(const char *name)
+{
+	int jobno;
+	struct job *found, *jp;
+	size_t namelen;
+	pid_t pid;
+	int i;
+
+	if (name == NULL) {
+#if JOBS
+		name = "%+";
+#else
+		error("No current job");
+#endif
+	}
+	if (name[0] == '%') {
+		if (is_digit(name[1])) {
+			jobno = number(name + 1);
+			if (jobno > 0 && jobno <= njobs
+			 && jobtab[jobno - 1].used != 0)
+				return &jobtab[jobno - 1];
+#if JOBS
+		} else if ((name[1] == '%' || name[1] == '+') &&
+		    name[2] == '\0') {
+			if ((jp = getcurjob(NULL)) == NULL)
+				error("No current job");
+			return (jp);
+		} else if (name[1] == '-' && name[2] == '\0') {
+			if ((jp = getcurjob(NULL)) == NULL ||
+			    (jp = getcurjob(jp)) == NULL)
+				error("No previous job");
+			return (jp);
+#endif
+		} else if (name[1] == '?') {
+			found = NULL;
+			for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
+				if (jp->used && jp->nprocs > 0
+				 && strstr(jp->ps[0].cmd, name + 2) != NULL) {
+					if (found)
+						error("%s: ambiguous", name);
+					found = jp;
+				}
+			}
+			if (found != NULL)
+				return (found);
+		} else {
+			namelen = strlen(name);
+			found = NULL;
+			for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
+				if (jp->used && jp->nprocs > 0
+				 && strncmp(jp->ps[0].cmd, name + 1,
+				 namelen - 1) == 0) {
+					if (found)
+						error("%s: ambiguous", name);
+					found = jp;
+				}
+			}
+			if (found)
+				return found;
+		}
+	} else if (is_number(name)) {
+		pid = (pid_t)number(name);
+		for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
+			if (jp->used && jp->nprocs > 0
+			 && jp->ps[jp->nprocs - 1].pid == pid)
+				return jp;
+		}
+	}
+	return NULL;
+}
+
+
+static struct job *
+getjob(const char *name)
+{
+	struct job *jp;
+
+	jp = getjob_nonotfound(name);
+	if (jp == NULL)
+		error("No such job: %s", name);
+	return (jp);
+}
+
+
+int
+killjob(const char *name, int sig)
+{
+	struct job *jp;
+	int i, ret;
+
+	jp = getjob(name);
+	if (jp->state == JOBDONE)
+		return 0;
+	if (jp->jobctl)
+		return kill(-jp->ps[0].pid, sig);
+	ret = -1;
+	errno = ESRCH;
+	for (i = 0; i < jp->nprocs; i++)
+		if (jp->ps[i].status == -1 || WIFSTOPPED(jp->ps[i].status)) {
+			if (kill(jp->ps[i].pid, sig) == 0)
+				ret = 0;
+		} else
+			ret = 0;
+	return ret;
+}
+
+/*
+ * Return a new job structure,
+ */
+
+struct job *
+makejob(union node *node __unused, int nprocs)
+{
+	int i;
+	struct job *jp;
+
+	for (i = njobs, jp = jobtab ; ; jp++) {
+		if (--i < 0) {
+			INTOFF;
+			if (njobs == 0) {
+				jobtab = ckmalloc(4 * sizeof jobtab[0]);
+#if JOBS
+				jobmru = NULL;
+#endif
+			} else {
+				jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
+				memcpy(jp, jobtab, njobs * sizeof jp[0]);
+#if JOBS
+				/* Relocate `next' pointers and list head */
+				if (jobmru != NULL)
+					jobmru = &jp[jobmru - jobtab];
+				for (i = 0; i < njobs; i++)
+					if (jp[i].next != NULL)
+						jp[i].next = &jp[jp[i].next -
+						    jobtab];
+#endif
+				if (bgjob != NULL)
+					bgjob = &jp[bgjob - jobtab];
+				/* Relocate `ps' pointers */
+				for (i = 0; i < njobs; i++)
+					if (jp[i].ps == &jobtab[i].ps0)
+						jp[i].ps = &jp[i].ps0;
+				ckfree(jobtab);
+				jobtab = jp;
+			}
+			jp = jobtab + njobs;
+			for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0)
+				;
+			INTON;
+			break;
+		}
+		if (jp->used == 0)
+			break;
+	}
+	INTOFF;
+	jp->state = 0;
+	jp->used = 1;
+	jp->changed = 0;
+	jp->nprocs = 0;
+	jp->foreground = 0;
+	jp->remembered = 0;
+	jp->pipefail = pipefailflag;
+#if JOBS
+	jp->jobctl = jobctl;
+	jp->next = NULL;
+#endif
+	if (nprocs > 1) {
+		jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
+	} else {
+		jp->ps = &jp->ps0;
+	}
+	INTON;
+	TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
+	    jp - jobtab + 1));
+	return jp;
+}
+
+#if JOBS
+static void
+setcurjob(struct job *cj)
+{
+	struct job *jp, *prev;
+
+	for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
+		if (jp == cj) {
+			if (prev != NULL)
+				prev->next = jp->next;
+			else
+				jobmru = jp->next;
+			jp->next = jobmru;
+			jobmru = cj;
+			return;
+		}
+	}
+	cj->next = jobmru;
+	jobmru = cj;
+}
+
+static void
+deljob(struct job *j)
+{
+	struct job *jp, *prev;
+
+	for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
+		if (jp == j) {
+			if (prev != NULL)
+				prev->next = jp->next;
+			else
+				jobmru = jp->next;
+			return;
+		}
+	}
+}
+
+/*
+ * Return the most recently used job that isn't `nj', and preferably one
+ * that is stopped.
+ */
+static struct job *
+getcurjob(struct job *nj)
+{
+	struct job *jp;
+
+	/* Try to find a stopped one.. */
+	for (jp = jobmru; jp != NULL; jp = jp->next)
+		if (jp->used && jp != nj && jp->state == JOBSTOPPED)
+			return (jp);
+	/* Otherwise the most recently used job that isn't `nj' */
+	for (jp = jobmru; jp != NULL; jp = jp->next)
+		if (jp->used && jp != nj)
+			return (jp);
+
+	return (NULL);
+}
+
+#endif
+
+/*
+ * Fork of a subshell.  If we are doing job control, give the subshell its
+ * own process group.  Jp is a job structure that the job is to be added to.
+ * N is the command that will be evaluated by the child.  Both jp and n may
+ * be NULL.  The mode parameter can be one of the following:
+ *	FORK_FG - Fork off a foreground process.
+ *	FORK_BG - Fork off a background process.
+ *	FORK_NOJOB - Like FORK_FG, but don't give the process its own
+ *		     process group even if job control is on.
+ *
+ * When job control is turned off, background processes have their standard
+ * input redirected to /dev/null (except for the second and later processes
+ * in a pipeline).
+ */
+
+pid_t
+forkshell(struct job *jp, union node *n, int mode)
+{
+	pid_t pid;
+	pid_t pgrp;
+
+	TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
+	    mode));
+	INTOFF;
+	if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
+		checkzombies();
+	flushall();
+	pid = fork();
+	if (pid == -1) {
+		TRACE(("Fork failed, errno=%d\n", errno));
+		INTON;
+		error("Cannot fork: %s", strerror(errno));
+	}
+	if (pid == 0) {
+		struct job *p;
+		int wasroot;
+		int i;
+
+		TRACE(("Child shell %d\n", (int)getpid()));
+		wasroot = rootshell;
+		rootshell = 0;
+		handler = &main_handler;
+		closescript();
+		INTON;
+		forcelocal = 0;
+		clear_traps();
+#if JOBS
+		jobctl = 0;		/* do job control only in root shell */
+		if (wasroot && mode != FORK_NOJOB && mflag) {
+			if (jp == NULL || jp->nprocs == 0)
+				pgrp = getpid();
+			else
+				pgrp = jp->ps[0].pid;
+			if (setpgid(0, pgrp) == 0 && mode == FORK_FG &&
+			    ttyfd >= 0) {
+				/*** this causes superfluous TIOCSPGRPS ***/
+				if (tcsetpgrp(ttyfd, pgrp) < 0)
+					error("tcsetpgrp failed, errno=%d", errno);
+			}
+			setsignal(SIGTSTP);
+			setsignal(SIGTTOU);
+		} else if (mode == FORK_BG) {
+			ignoresig(SIGINT);
+			ignoresig(SIGQUIT);
+			if ((jp == NULL || jp->nprocs == 0) &&
+			    ! fd0_redirected_p ()) {
+				close(0);
+				if (open(_PATH_DEVNULL, O_RDONLY) != 0)
+					error("cannot open %s: %s",
+					    _PATH_DEVNULL, strerror(errno));
+			}
+		}
+#else
+		if (mode == FORK_BG) {
+			ignoresig(SIGINT);
+			ignoresig(SIGQUIT);
+			if ((jp == NULL || jp->nprocs == 0) &&
+			    ! fd0_redirected_p ()) {
+				close(0);
+				if (open(_PATH_DEVNULL, O_RDONLY) != 0)
+					error("cannot open %s: %s",
+					    _PATH_DEVNULL, strerror(errno));
+			}
+		}
+#endif
+		INTOFF;
+		for (i = njobs, p = jobtab ; --i >= 0 ; p++)
+			if (p->used)
+				freejob(p);
+		INTON;
+		if (wasroot && iflag) {
+			setsignal(SIGINT);
+			setsignal(SIGQUIT);
+			setsignal(SIGTERM);
+		}
+		return pid;
+	}
+	if (rootshell && mode != FORK_NOJOB && mflag) {
+		if (jp == NULL || jp->nprocs == 0)
+			pgrp = pid;
+		else
+			pgrp = jp->ps[0].pid;
+		setpgid(pid, pgrp);
+	}
+	if (mode == FORK_BG) {
+		if (bgjob != NULL && bgjob->state == JOBDONE &&
+		    !bgjob->remembered && !iflag)
+			freejob(bgjob);
+		backgndpid = pid;		/* set $! */
+		bgjob = jp;
+	}
+	if (jp) {
+		struct procstat *ps = &jp->ps[jp->nprocs++];
+		ps->pid = pid;
+		ps->status = -1;
+		ps->cmd = nullstr;
+		if (iflag && rootshell && n)
+			ps->cmd = commandtext(n);
+		jp->foreground = mode == FORK_FG;
+#if JOBS
+		setcurjob(jp);
+#endif
+	}
+	INTON;
+	TRACE(("In parent shell:  child = %d\n", (int)pid));
+	return pid;
+}
+
+
+pid_t
+vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
+{
+	pid_t pid;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+
+	TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
+	    (void *)pip));
+	INTOFF;
+	flushall();
+	savehandler = handler;
+	pid = vfork();
+	if (pid == -1) {
+		TRACE(("Vfork failed, errno=%d\n", errno));
+		INTON;
+		error("Cannot fork: %s", strerror(errno));
+	}
+	if (pid == 0) {
+		TRACE(("Child shell %d\n", (int)getpid()));
+		if (setjmp(jmploc.loc))
+			_exit(exception == EXEXEC ? exerrno : 2);
+		if (pip != NULL) {
+			close(pip[0]);
+			if (pip[1] != 1) {
+				dup2(pip[1], 1);
+				close(pip[1]);
+			}
+		}
+		handler = &jmploc;
+		shellexec(argv, envp, path, idx);
+	}
+	handler = savehandler;
+	if (jp) {
+		struct procstat *ps = &jp->ps[jp->nprocs++];
+		ps->pid = pid;
+		ps->status = -1;
+		ps->cmd = nullstr;
+		jp->foreground = 1;
+#if JOBS
+		setcurjob(jp);
+#endif
+	}
+	INTON;
+	TRACE(("In parent shell:  child = %d\n", (int)pid));
+	return pid;
+}
+
+
+/*
+ * Wait for job to finish.
+ *
+ * Under job control we have the problem that while a child process is
+ * running interrupts generated by the user are sent to the child but not
+ * to the shell.  This means that an infinite loop started by an inter-
+ * active user may be hard to kill.  With job control turned off, an
+ * interactive user may place an interactive program inside a loop.  If
+ * the interactive program catches interrupts, the user doesn't want
+ * these interrupts to also abort the loop.  The approach we take here
+ * is to have the shell ignore interrupt signals while waiting for a
+ * foreground process to terminate, and then send itself an interrupt
+ * signal if the child process was terminated by an interrupt signal.
+ * Unfortunately, some programs want to do a bit of cleanup and then
+ * exit on interrupt; unless these processes terminate themselves by
+ * sending a signal to themselves (instead of calling exit) they will
+ * confuse this approach.
+ */
+
+int
+waitforjob(struct job *jp, int *signaled)
+{
+#if JOBS
+	int propagate_int = jp->jobctl && jp->foreground;
+#endif
+	int status;
+	int st;
+
+	INTOFF;
+	TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
+	while (jp->state == 0)
+		if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG |
+		    DOWAIT_SIG_TRAP : 0), jp) == -1)
+			dotrap();
+#if JOBS
+	if (jp->jobctl) {
+		if (ttyfd >= 0 && tcsetpgrp(ttyfd, rootpid) < 0)
+			error("tcsetpgrp failed, errno=%d\n", errno);
+	}
+	if (jp->state == JOBSTOPPED)
+		setcurjob(jp);
+#endif
+	status = getjobstatus(jp);
+	if (signaled != NULL)
+		*signaled = WIFSIGNALED(status);
+	/* convert to 8 bits */
+	if (WIFEXITED(status))
+		st = WEXITSTATUS(status);
+#if JOBS
+	else if (WIFSTOPPED(status))
+		st = WSTOPSIG(status) + 128;
+#endif
+	else
+		st = WTERMSIG(status) + 128;
+	if (! JOBS || jp->state == JOBDONE)
+		freejob(jp);
+	if (int_pending()) {
+		if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
+			CLEAR_PENDING_INT;
+	}
+#if JOBS
+	else if (rootshell && propagate_int &&
+			WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
+		kill(getpid(), SIGINT);
+#endif
+	INTON;
+	return st;
+}
+
+
+static void
+dummy_handler(int sig __unused)
+{
+}
+
+/*
+ * Wait for a process to terminate.
+ */
+
+static pid_t
+dowait(int mode, struct job *job)
+{
+	struct sigaction sa, osa;
+	sigset_t mask, omask;
+	pid_t pid;
+	int status;
+	struct procstat *sp;
+	struct job *jp;
+	struct job *thisjob;
+	const char *sigstr;
+	int done;
+	int stopped;
+	int sig;
+	int coredump;
+	int wflags;
+	int restore_sigchld;
+
+	TRACE(("dowait(%d, %p) called\n", mode, job));
+	restore_sigchld = 0;
+	if ((mode & DOWAIT_SIG) != 0) {
+		sigfillset(&mask);
+		sigprocmask(SIG_BLOCK, &mask, &omask);
+		INTOFF;
+		if (!issigchldtrapped()) {
+			restore_sigchld = 1;
+			sa.sa_handler = dummy_handler;
+			sa.sa_flags = 0;
+			sigemptyset(&sa.sa_mask);
+			sigaction(SIGCHLD, &sa, &osa);
+		}
+	}
+	do {
+#if JOBS
+		if (iflag)
+			wflags = WUNTRACED | WCONTINUED;
+		else
+#endif
+			wflags = 0;
+		if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
+			wflags |= WNOHANG;
+		pid = wait3(&status, wflags, (struct rusage *)NULL);
+		TRACE(("wait returns %d, status=%d\n", (int)pid, status));
+		if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
+			pid = -1;
+			if (((mode & DOWAIT_SIG_TRAP) != 0 ?
+			    pendingsig : pendingsig_waitcmd) != 0) {
+				errno = EINTR;
+				break;
+			}
+			sigsuspend(&omask);
+			if (int_pending())
+				break;
+		}
+	} while (pid == -1 && errno == EINTR);
+	if (pid == -1 && errno == ECHILD && job != NULL)
+		job->state = JOBDONE;
+	if ((mode & DOWAIT_SIG) != 0) {
+		if (restore_sigchld)
+			sigaction(SIGCHLD, &osa, NULL);
+		sigprocmask(SIG_SETMASK, &omask, NULL);
+		INTON;
+	}
+	if (pid <= 0)
+		return pid;
+	INTOFF;
+	thisjob = NULL;
+	for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
+		if (jp->used && jp->nprocs > 0) {
+			done = 1;
+			stopped = 1;
+			for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
+				if (sp->pid == -1)
+					continue;
+				if (sp->pid == pid && (sp->status == -1 ||
+				    WIFSTOPPED(sp->status))) {
+					TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
+						   (int)pid, sp->status,
+						   status));
+					if (WIFCONTINUED(status)) {
+						sp->status = -1;
+						jp->state = 0;
+					} else
+						sp->status = status;
+					thisjob = jp;
+				}
+				if (sp->status == -1)
+					stopped = 0;
+				else if (WIFSTOPPED(sp->status))
+					done = 0;
+			}
+			if (stopped) {		/* stopped or done */
+				int state = done? JOBDONE : JOBSTOPPED;
+				if (jp->state != state) {
+					TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
+					jp->state = state;
+					if (jp != job) {
+						if (done && !jp->remembered &&
+						    !iflag && jp != bgjob)
+							freejob(jp);
+#if JOBS
+						else if (done)
+							deljob(jp);
+#endif
+					}
+				}
+			}
+		}
+	}
+	INTON;
+	if (!thisjob || thisjob->state == 0)
+		;
+	else if ((!rootshell || !iflag || thisjob == job) &&
+	    thisjob->foreground && thisjob->state != JOBSTOPPED) {
+		sig = 0;
+		coredump = 0;
+		for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
+			if (WIFSIGNALED(sp->status)) {
+				sig = WTERMSIG(sp->status);
+				coredump = WCOREDUMP(sp->status);
+			}
+		if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
+			sigstr = strsignal(sig);
+			if (sigstr != NULL)
+				out2str(sigstr);
+			else
+				out2str("Unknown signal");
+			if (coredump)
+				out2str(" (core dumped)");
+			out2c('\n');
+			flushout(out2);
+		}
+	} else {
+		TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
+		thisjob->changed = 1;
+	}
+	return pid;
+}
+
+
+
+/*
+ * return 1 if there are stopped jobs, otherwise 0
+ */
+int job_warning = 0;
+int
+stoppedjobs(void)
+{
+	int jobno;
+	struct job *jp;
+
+	if (job_warning)
+		return (0);
+	for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
+		if (jp->used == 0)
+			continue;
+		if (jp->state == JOBSTOPPED) {
+			out2fmt_flush("You have stopped jobs.\n");
+			job_warning = 2;
+			return (1);
+		}
+	}
+
+	return (0);
+}
+
+
+static void
+checkzombies(void)
+{
+	while (njobs > 0 && dowait(0, NULL) > 0)
+		;
+}
+
+
+int
+backgndpidset(void)
+{
+	return backgndpid != -1;
+}
+
+
+pid_t
+backgndpidval(void)
+{
+	if (bgjob != NULL && !forcelocal)
+		bgjob->remembered = 1;
+	return backgndpid;
+}
+
+/*
+ * Return a string identifying a command (to be printed by the
+ * jobs command.
+ */
+
+static char *cmdnextc;
+static int cmdnleft;
+#define MAXCMDTEXT	200
+
+char *
+commandtext(union node *n)
+{
+	char *name;
+
+	cmdnextc = name = ckmalloc(MAXCMDTEXT);
+	cmdnleft = MAXCMDTEXT - 4;
+	cmdtxt(n);
+	*cmdnextc = '\0';
+	return name;
+}
+
+
+static void
+cmdtxtdogroup(union node *n)
+{
+	cmdputs("; do ");
+	cmdtxt(n);
+	cmdputs("; done");
+}
+
+
+static void
+cmdtxtredir(union node *n, const char *op, int deffd)
+{
+	char s[2];
+
+	if (n->nfile.fd != deffd) {
+		s[0] = n->nfile.fd + '0';
+		s[1] = '\0';
+		cmdputs(s);
+	}
+	cmdputs(op);
+	if (n->type == NTOFD || n->type == NFROMFD) {
+		if (n->ndup.dupfd >= 0)
+			s[0] = n->ndup.dupfd + '0';
+		else
+			s[0] = '-';
+		s[1] = '\0';
+		cmdputs(s);
+	} else {
+		cmdtxt(n->nfile.fname);
+	}
+}
+
+
+static void
+cmdtxt(union node *n)
+{
+	union node *np;
+	struct nodelist *lp;
+
+	if (n == NULL)
+		return;
+	switch (n->type) {
+	case NSEMI:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs("; ");
+		cmdtxt(n->nbinary.ch2);
+		break;
+	case NAND:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs(" && ");
+		cmdtxt(n->nbinary.ch2);
+		break;
+	case NOR:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs(" || ");
+		cmdtxt(n->nbinary.ch2);
+		break;
+	case NPIPE:
+		for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
+			cmdtxt(lp->n);
+			if (lp->next)
+				cmdputs(" | ");
+		}
+		break;
+	case NSUBSHELL:
+		cmdputs("(");
+		cmdtxt(n->nredir.n);
+		cmdputs(")");
+		break;
+	case NREDIR:
+	case NBACKGND:
+		cmdtxt(n->nredir.n);
+		break;
+	case NIF:
+		cmdputs("if ");
+		cmdtxt(n->nif.test);
+		cmdputs("; then ");
+		cmdtxt(n->nif.ifpart);
+		cmdputs("...");
+		break;
+	case NWHILE:
+		cmdputs("while ");
+		cmdtxt(n->nbinary.ch1);
+		cmdtxtdogroup(n->nbinary.ch2);
+		break;
+	case NUNTIL:
+		cmdputs("until ");
+		cmdtxt(n->nbinary.ch1);
+		cmdtxtdogroup(n->nbinary.ch2);
+		break;
+	case NFOR:
+		cmdputs("for ");
+		cmdputs(n->nfor.var);
+		cmdputs(" in ...");
+		break;
+	case NCASE:
+		cmdputs("case ");
+		cmdputs(n->ncase.expr->narg.text);
+		cmdputs(" in ...");
+		break;
+	case NDEFUN:
+		cmdputs(n->narg.text);
+		cmdputs("() ...");
+		break;
+	case NNOT:
+		cmdputs("! ");
+		cmdtxt(n->nnot.com);
+		break;
+	case NCMD:
+		for (np = n->ncmd.args ; np ; np = np->narg.next) {
+			cmdtxt(np);
+			if (np->narg.next)
+				cmdputs(" ");
+		}
+		for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
+			cmdputs(" ");
+			cmdtxt(np);
+		}
+		break;
+	case NARG:
+		cmdputs(n->narg.text);
+		break;
+	case NTO:
+		cmdtxtredir(n, ">", 1);
+		break;
+	case NAPPEND:
+		cmdtxtredir(n, ">>", 1);
+		break;
+	case NTOFD:
+		cmdtxtredir(n, ">&", 1);
+		break;
+	case NCLOBBER:
+		cmdtxtredir(n, ">|", 1);
+		break;
+	case NFROM:
+		cmdtxtredir(n, "<", 0);
+		break;
+	case NFROMTO:
+		cmdtxtredir(n, "<>", 0);
+		break;
+	case NFROMFD:
+		cmdtxtredir(n, "<&", 0);
+		break;
+	case NHERE:
+	case NXHERE:
+		cmdputs("<<...");
+		break;
+	default:
+		cmdputs("???");
+		break;
+	}
+}
+
+
+
+static void
+cmdputs(const char *s)
+{
+	const char *p;
+	char *q;
+	char c;
+	int subtype = 0;
+
+	if (cmdnleft <= 0)
+		return;
+	p = s;
+	q = cmdnextc;
+	while ((c = *p++) != '\0') {
+		if (c == CTLESC)
+			*q++ = *p++;
+		else if (c == CTLVAR) {
+			*q++ = '$';
+			if (--cmdnleft > 0)
+				*q++ = '{';
+			subtype = *p++;
+			if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
+				*q++ = '#';
+		} else if (c == '=' && subtype != 0) {
+			*q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
+			if (*q)
+				q++;
+			else
+				cmdnleft++;
+			if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
+			    (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
+			    --cmdnleft > 0)
+				*q = q[-1], q++;
+			subtype = 0;
+		} else if (c == CTLENDVAR) {
+			*q++ = '}';
+		} else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
+			cmdnleft -= 5;
+			if (cmdnleft > 0) {
+				*q++ = '$';
+				*q++ = '(';
+				*q++ = '.';
+				*q++ = '.';
+				*q++ = '.';
+				*q++ = ')';
+			}
+		} else if (c == CTLARI) {
+			cmdnleft -= 2;
+			if (cmdnleft > 0) {
+				*q++ = '$';
+				*q++ = '(';
+				*q++ = '(';
+			}
+			p++;
+		} else if (c == CTLENDARI) {
+			if (--cmdnleft > 0) {
+				*q++ = ')';
+				*q++ = ')';
+			}
+		} else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
+			cmdnleft++; /* ignore */
+		else
+			*q++ = c;
+		if (--cmdnleft <= 0) {
+			*q++ = '.';
+			*q++ = '.';
+			*q++ = '.';
+			break;
+		}
+	}
+	cmdnextc = q;
+}
diff --git a/bin/1sh/jobs.h b/bin/1sh/jobs.h
new file mode 100644
index 00000000..98c2eb5c
--- /dev/null
+++ b/bin/1sh/jobs.h
@@ -0,0 +1,67 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)jobs.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/jobs.h 327475 2018-01-01 22:31:52Z jilles $
+ */
+
+/* Mode argument to forkshell.  Don't change FORK_FG or FORK_BG. */
+#define FORK_FG 0
+#define FORK_BG 1
+#define FORK_NOJOB 2
+
+#include <signal.h>		/* for sig_atomic_t */
+
+struct job;
+
+enum {
+	SHOWJOBS_DEFAULT,	/* job number, status, command */
+	SHOWJOBS_VERBOSE,	/* job number, PID, status, command */
+	SHOWJOBS_PIDS,		/* PID only */
+	SHOWJOBS_PGIDS		/* PID of the group leader only */
+};
+
+extern int job_warning;		/* user was warned about stopped jobs */
+
+void setjobctl(int);
+void showjobs(int, int);
+struct job *makejob(union node *, int);
+pid_t forkshell(struct job *, union node *, int);
+pid_t vforkexecshell(struct job *, char **, char **, const char *, int, int []);
+int waitforjob(struct job *, int *);
+int stoppedjobs(void);
+int backgndpidset(void);
+pid_t backgndpidval(void);
+char *commandtext(union node *);
+
+#if ! JOBS
+#define setjobctl(on)	/* do nothing */
+#endif
diff --git a/bin/1sh/kill.c b/bin/1sh/kill.c
new file mode 100644
index 00000000..6003fa9d
--- /dev/null
+++ b/bin/1sh/kill.c
@@ -0,0 +1,215 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1988, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * Important: This file is used both as a standalone program /bin/kill and
+ * as a builtin for /bin/sh (#define SHELL).
+ */
+
+#if 0
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1988, 1993, 1994\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)kill.c	8.4 (Berkeley) 4/28/95";
+#endif /* not lint */
+#endif
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/kill/kill.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef SHELL
+#define main killcmd
+#include "bltin.h"
+#endif
+
+static void nosig(const char *);
+static void printsignals(FILE *);
+static int signame_to_signum(const char *);
+static void usage(void);
+
+int
+main(int argc, char *argv[])
+{
+	long pidl;
+	pid_t pid;
+	int errors, numsig, ret;
+	char *ep;
+
+	if (argc < 2)
+		usage();
+
+	numsig = SIGTERM;
+
+	argc--, argv++;
+	if (!strcmp(*argv, "-l")) {
+		argc--, argv++;
+		if (argc > 1)
+			usage();
+		if (argc == 1) {
+			if (!isdigit(**argv))
+				usage();
+			numsig = strtol(*argv, &ep, 10);
+			if (!**argv || *ep)
+				errx(2, "illegal signal number: %s", *argv);
+			if (numsig >= 128)
+				numsig -= 128;
+			if (numsig <= 0 || numsig >= NSIG)
+				nosig(*argv);
+			printf("%s\n", sys_signame[numsig]);
+			return (0);
+		}
+		printsignals(stdout);
+		return (0);
+	}
+
+	if (!strcmp(*argv, "-s")) {
+		argc--, argv++;
+		if (argc < 1) {
+			warnx("option requires an argument -- s");
+			usage();
+		}
+		if (strcmp(*argv, "0")) {
+			if ((numsig = signame_to_signum(*argv)) < 0)
+				nosig(*argv);
+		} else
+			numsig = 0;
+		argc--, argv++;
+	} else if (**argv == '-' && *(*argv + 1) != '-') {
+		++*argv;
+		if (isalpha(**argv)) {
+			if ((numsig = signame_to_signum(*argv)) < 0)
+				nosig(*argv);
+		} else if (isdigit(**argv)) {
+			numsig = strtol(*argv, &ep, 10);
+			if (!**argv || *ep)
+				errx(2, "illegal signal number: %s", *argv);
+			if (numsig < 0)
+				nosig(*argv);
+		} else
+			nosig(*argv);
+		argc--, argv++;
+	}
+
+	if (argc > 0 && strncmp(*argv, "--", 2) == 0)
+		argc--, argv++;
+
+	if (argc == 0)
+		usage();
+
+	for (errors = 0; argc; argc--, argv++) {
+#ifdef SHELL
+		if (**argv == '%')
+			ret = killjob(*argv, numsig);
+		else
+#endif
+		{
+			pidl = strtol(*argv, &ep, 10);
+			/* Check for overflow of pid_t. */
+			pid = (pid_t)pidl;
+			if (!**argv || *ep || pid != pidl)
+				errx(2, "illegal process id: %s", *argv);
+			ret = kill(pid, numsig);
+		}
+		if (ret == -1) {
+			warn("%s", *argv);
+			errors = 1;
+		}
+	}
+
+	return (errors);
+}
+
+static int
+signame_to_signum(const char *sig)
+{
+	int n;
+
+	if (strncasecmp(sig, "SIG", 3) == 0)
+		sig += 3;
+	for (n = 1; n < NSIG; n++) {
+		if (!strcasecmp(sys_signame[n], sig))
+			return (n);
+	}
+	return (-1);
+}
+
+static void
+nosig(const char *name)
+{
+
+	warnx("unknown signal %s; valid signals:", name);
+	printsignals(stderr);
+#ifdef SHELL
+	error(NULL);
+#else
+	exit(2);
+#endif
+}
+
+static void
+printsignals(FILE *fp)
+{
+	int n;
+
+	for (n = 1; n < NSIG; n++) {
+		(void)fprintf(fp, "%s", sys_signame[n]);
+		if (n == (NSIG / 2) || n == (NSIG - 1))
+			(void)fprintf(fp, "\n");
+		else
+			(void)fprintf(fp, " ");
+	}
+}
+
+static void
+usage(void)
+{
+
+	(void)fprintf(stderr, "%s\n%s\n%s\n%s\n",
+		"usage: kill [-s signal_name] pid ...",
+		"       kill -l [exit_status]",
+		"       kill -signal_name pid ...",
+		"       kill -signal_number pid ...");
+#ifdef SHELL
+	error(NULL);
+#else
+	exit(2);
+#endif
+}
diff --git a/bin/1sh/mail.c b/bin/1sh/mail.c
new file mode 100644
index 00000000..adf54a06
--- /dev/null
+++ b/bin/1sh/mail.c
@@ -0,0 +1,120 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)mail.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/mail.c 336303 2018-07-15 09:14:30Z jilles $ */
+
+/*
+ * Routines to check for mail.  (Perhaps make part of main.c?)
+ */
+
+#include "shell.h"
+#include "mail.h"
+#include "var.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+
+
+#define MAXMBOXES 10
+
+
+static int nmboxes;			/* number of mailboxes */
+static time_t mailtime[MAXMBOXES];	/* times of mailboxes */
+
+
+
+/*
+ * Print appropriate message(s) if mail has arrived.  If the argument is
+ * nozero, then the value of MAIL has changed, so we just update the
+ * values.
+ */
+
+void
+chkmail(int silent)
+{
+	int i;
+	char *mpath;
+	char *p;
+	char *msg;
+	struct stackmark smark;
+	struct stat statb;
+
+	if (silent)
+		nmboxes = 10;
+	if (nmboxes == 0)
+		return;
+	setstackmark(&smark);
+	mpath = stsavestr(mpathset()? mpathval() : mailval());
+	for (i = 0 ; i < nmboxes ; i++) {
+		p = mpath;
+		if (*p == '\0')
+			break;
+		mpath = strchr(p, ':');
+		if (!mpath) mpath = strchr(p, '\0');
+		if (*mpath != '\0') {
+			*mpath++ = '\0';
+			if (p == mpath - 1)
+				continue;
+		}
+		msg = strchr(p, '%');
+		if (msg != NULL)
+			*msg++ = '\0';
+#ifdef notdef /* this is what the System V shell claims to do (it lies) */
+		if (stat(p, &statb) < 0)
+			statb.st_mtime = 0;
+		if (statb.st_mtime > mailtime[i] && ! silent) {
+			out2str(msg? msg : "you have mail");
+			out2c('\n');
+		}
+		mailtime[i] = statb.st_mtime;
+#else /* this is what it should do */
+		if (stat(p, &statb) < 0)
+			statb.st_size = 0;
+		if (statb.st_size > mailtime[i] && ! silent) {
+			out2str(msg? msg : "you have mail");
+			out2c('\n');
+		}
+		mailtime[i] = statb.st_size;
+#endif
+	}
+	nmboxes = i;
+	popstackmark(&smark);
+}
diff --git a/bin/1sh/mail.h b/bin/1sh/mail.h
new file mode 100644
index 00000000..bc124ba3
--- /dev/null
+++ b/bin/1sh/mail.h
@@ -0,0 +1,38 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)mail.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/mail.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+void chkmail(int);
diff --git a/bin/1sh/main.c b/bin/1sh/main.c
new file mode 100644
index 00000000..3f0bc1da
--- /dev/null
+++ b/bin/1sh/main.c
@@ -0,0 +1,356 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if 0
+static char const copyright[] =
+"@(#) Copyright (c) 1991, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/28/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/main.c 336320 2018-07-15 21:55:17Z jilles $ */
+
+#include <stdio.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <errno.h>
+
+#include "shell.h"
+#include "main.h"
+#include "mail.h"
+#include "options.h"
+#include "output.h"
+#include "parser.h"
+#include "nodes.h"
+#include "expand.h"
+#include "eval.h"
+#include "jobs.h"
+#include "input.h"
+#include "trap.h"
+#include "var.h"
+#include "show.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "exec.h"
+#include "cd.h"
+#include "redir.h"
+#include "builtins.h"
+
+int rootpid;
+int rootshell;
+struct jmploc main_handler;
+int localeisutf8, initial_localeisutf8;
+
+static void reset(void);
+static void cmdloop(int);
+static void read_profile(const char *);
+static char *find_dot_file(char *);
+
+/*
+ * Main routine.  We initialize things, parse the arguments, execute
+ * profiles if we're a login shell, and then call cmdloop to execute
+ * commands.  The setjmp call sets up the location to jump to when an
+ * exception occurs.  When an exception occurs the variable "state"
+ * is used to figure out how far we had gotten.
+ */
+
+int
+main(int argc, char *argv[])
+{
+	struct stackmark smark, smark2;
+	volatile int state;
+	char *shinit;
+
+	(void) setlocale(LC_ALL, "");
+	initcharset();
+	state = 0;
+	if (setjmp(main_handler.loc)) {
+		switch (exception) {
+		case EXEXEC:
+			exitstatus = exerrno;
+			break;
+
+		case EXERROR:
+			exitstatus = 2;
+			break;
+
+		default:
+			break;
+		}
+
+		if (state == 0 || iflag == 0 || ! rootshell ||
+		    exception == EXEXIT)
+			exitshell(exitstatus);
+		reset();
+		if (exception == EXINT)
+			out2fmt_flush("\n");
+		popstackmark(&smark);
+		FORCEINTON;				/* enable interrupts */
+		if (state == 1)
+			goto state1;
+		else if (state == 2)
+			goto state2;
+		else if (state == 3)
+			goto state3;
+		else
+			goto state4;
+	}
+	handler = &main_handler;
+#ifdef DEBUG
+	opentrace();
+	trputs("Shell args:  ");  trargs(argv);
+#endif
+	rootpid = getpid();
+	rootshell = 1;
+	INTOFF;
+	initvar();
+	setstackmark(&smark);
+	setstackmark(&smark2);
+	procargs(argc, argv);
+	pwd_init(iflag);
+	INTON;
+	if (iflag)
+		chkmail(1);
+	if (argv[0] && argv[0][0] == '-') {
+		state = 1;
+		read_profile("/etc/profile");
+state1:
+		state = 2;
+		if (privileged == 0)
+			read_profile("${HOME-}/.profile");
+		else
+			read_profile("/etc/suid_profile");
+	}
+state2:
+	state = 3;
+	if (!privileged && iflag) {
+		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
+			state = 3;
+			read_profile(shinit);
+		}
+	}
+state3:
+	state = 4;
+	popstackmark(&smark2);
+	if (minusc) {
+		evalstring(minusc, sflag ? 0 : EV_EXIT);
+	}
+state4:
+	if (sflag || minusc == NULL) {
+		cmdloop(1);
+	}
+	iflag = 0;
+	optschanged();
+	exitshell(exitstatus);
+	/*NOTREACHED*/
+	return 0;
+}
+
+static void
+reset(void)
+{
+	reseteval();
+	resetinput();
+}
+
+/*
+ * Read and execute commands.  "Top" is nonzero for the top level command
+ * loop; it turns on prompting if the shell is interactive.
+ */
+
+static void
+cmdloop(int top)
+{
+	union node *n;
+	struct stackmark smark;
+	int inter;
+	int numeof = 0;
+
+	TRACE(("cmdloop(%d) called\n", top));
+	setstackmark(&smark);
+	for (;;) {
+		if (pendingsig)
+			dotrap();
+		inter = 0;
+		if (iflag && top) {
+			inter++;
+			showjobs(1, SHOWJOBS_DEFAULT);
+			chkmail(0);
+			flushout(&output);
+		}
+		n = parsecmd(inter);
+		/* showtree(n); DEBUG */
+		if (n == NEOF) {
+			if (!top || numeof >= 50)
+				break;
+			if (!stoppedjobs()) {
+				if (!Iflag)
+					break;
+				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
+			}
+			numeof++;
+		} else if (n != NULL && nflag == 0) {
+			job_warning = (job_warning == 2) ? 1 : 0;
+			numeof = 0;
+			evaltree(n, 0);
+		}
+		popstackmark(&smark);
+		setstackmark(&smark);
+		if (evalskip != 0) {
+			if (evalskip == SKIPRETURN)
+				evalskip = 0;
+			break;
+		}
+	}
+	popstackmark(&smark);
+}
+
+
+
+/*
+ * Read /etc/profile or .profile.  Return on error.
+ */
+
+static void
+read_profile(const char *name)
+{
+	int fd;
+	const char *expandedname;
+
+	expandedname = expandstr(name);
+	if (expandedname == NULL)
+		return;
+	INTOFF;
+	if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 0)
+		setinputfd(fd, 1);
+	INTON;
+	if (fd < 0)
+		return;
+	cmdloop(0);
+	popfile();
+}
+
+
+
+/*
+ * Read a file containing shell functions.
+ */
+
+void
+readcmdfile(const char *name)
+{
+	setinputfile(name, 1);
+	cmdloop(0);
+	popfile();
+}
+
+
+
+/*
+ * Take commands from a file.  To be compatible we should do a path
+ * search for the file, which is necessary to find sub-commands.
+ */
+
+
+static char *
+find_dot_file(char *basename)
+{
+	char *fullname;
+	const char *opt;
+	const char *path = pathval();
+	struct stat statb;
+
+	/* don't try this for absolute or relative paths */
+	if( strchr(basename, '/'))
+		return basename;
+
+	while ((fullname = padvance(&path, &opt, basename)) != NULL) {
+		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
+			/*
+			 * Don't bother freeing here, since it will
+			 * be freed by the caller.
+			 */
+			return fullname;
+		}
+		stunalloc(fullname);
+	}
+	return basename;
+}
+
+int
+dotcmd(int argc, char **argv)
+{
+	char *filename, *fullname;
+
+	if (argc < 2)
+		error("missing filename");
+
+	exitstatus = 0;
+
+	/*
+	 * Because we have historically not supported any options,
+	 * only treat "--" specially.
+	 */
+	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
+
+	fullname = find_dot_file(filename);
+	setinputfile(fullname, 1);
+	commandname = fullname;
+	cmdloop(0);
+	popfile();
+	return exitstatus;
+}
+
+
+int
+exitcmd(int argc, char **argv)
+{
+	if (stoppedjobs())
+		return 0;
+	iflag = 0;
+	optschanged();
+	if (argc > 1)
+		exitshell(number(argv[1]));
+	else
+		exitshell_savedstatus();
+}
diff --git a/bin/1sh/main.h b/bin/1sh/main.h
new file mode 100644
index 00000000..329a5c8b
--- /dev/null
+++ b/bin/1sh/main.h
@@ -0,0 +1,42 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)main.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/main.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+extern int rootpid;	/* pid of main shell */
+extern int rootshell;	/* true if we aren't a child of the main shell */
+extern struct jmploc main_handler;	/* top level exception handler */
+
+void readcmdfile(const char *);
diff --git a/bin/1sh/memalloc.c b/bin/1sh/memalloc.c
new file mode 100644
index 00000000..c53521ad
--- /dev/null
+++ b/bin/1sh/memalloc.c
@@ -0,0 +1,344 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)memalloc.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/memalloc.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+#include <sys/param.h>
+#include "shell.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "expand.h"
+#include <stdlib.h>
+#include <unistd.h>
+
+/*
+ * Like malloc, but returns an error when out of space.
+ */
+
+pointer
+ckmalloc(size_t nbytes)
+{
+	pointer p;
+
+	INTOFF;
+	p = malloc(nbytes);
+	INTON;
+	if (p == NULL)
+		error("Out of space");
+	return p;
+}
+
+
+/*
+ * Same for realloc.
+ */
+
+pointer
+ckrealloc(pointer p, int nbytes)
+{
+	INTOFF;
+	p = realloc(p, nbytes);
+	INTON;
+	if (p == NULL)
+		error("Out of space");
+	return p;
+}
+
+void
+ckfree(pointer p)
+{
+	INTOFF;
+	free(p);
+	INTON;
+}
+
+
+/*
+ * Make a copy of a string in safe storage.
+ */
+
+char *
+savestr(const char *s)
+{
+	char *p;
+	size_t len;
+
+	len = strlen(s);
+	p = ckmalloc(len + 1);
+	memcpy(p, s, len + 1);
+	return p;
+}
+
+
+/*
+ * Parse trees for commands are allocated in lifo order, so we use a stack
+ * to make this more efficient, and also to avoid all sorts of exception
+ * handling code to handle interrupts in the middle of a parse.
+ *
+ * The size 496 was chosen because with 16-byte alignment the total size
+ * for the allocated block is 512.
+ */
+
+#define MINSIZE 496		/* minimum size of a block. */
+
+
+struct stack_block {
+	struct stack_block *prev;
+	/* Data follows */
+};
+#define SPACE(sp)	((char*)(sp) + ALIGN(sizeof(struct stack_block)))
+
+static struct stack_block *stackp;
+char *stacknxt;
+int stacknleft;
+char *sstrend;
+
+
+static void
+stnewblock(int nbytes)
+{
+	struct stack_block *sp;
+	int allocsize;
+
+	if (nbytes < MINSIZE)
+		nbytes = MINSIZE;
+
+	allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
+
+	INTOFF;
+	sp = ckmalloc(allocsize);
+	sp->prev = stackp;
+	stacknxt = SPACE(sp);
+	stacknleft = allocsize - (stacknxt - (char*)sp);
+	sstrend = stacknxt + stacknleft;
+	stackp = sp;
+	INTON;
+}
+
+
+pointer
+stalloc(int nbytes)
+{
+	char *p;
+
+	nbytes = ALIGN(nbytes);
+	if (nbytes > stacknleft)
+		stnewblock(nbytes);
+	p = stacknxt;
+	stacknxt += nbytes;
+	stacknleft -= nbytes;
+	return p;
+}
+
+
+void
+stunalloc(pointer p)
+{
+	if (p == NULL) {		/*DEBUG */
+		write(STDERR_FILENO, "stunalloc\n", 10);
+		abort();
+	}
+	stacknleft += stacknxt - (char *)p;
+	stacknxt = p;
+}
+
+
+char *
+stsavestr(const char *s)
+{
+	char *p;
+	size_t len;
+
+	len = strlen(s);
+	p = stalloc(len + 1);
+	memcpy(p, s, len + 1);
+	return p;
+}
+
+
+void
+setstackmark(struct stackmark *mark)
+{
+	mark->stackp = stackp;
+	mark->stacknxt = stacknxt;
+	mark->stacknleft = stacknleft;
+	/* Ensure this block stays in place. */
+	if (stackp != NULL && stacknxt == SPACE(stackp))
+		stalloc(1);
+}
+
+
+void
+popstackmark(struct stackmark *mark)
+{
+	struct stack_block *sp;
+
+	INTOFF;
+	while (stackp != mark->stackp) {
+		sp = stackp;
+		stackp = sp->prev;
+		ckfree(sp);
+	}
+	stacknxt = mark->stacknxt;
+	stacknleft = mark->stacknleft;
+	sstrend = stacknxt + stacknleft;
+	INTON;
+}
+
+
+/*
+ * When the parser reads in a string, it wants to stick the string on the
+ * stack and only adjust the stack pointer when it knows how big the
+ * string is.  Stackblock (defined in stack.h) returns a pointer to a block
+ * of space on top of the stack and stackblocklen returns the length of
+ * this block.  Growstackblock will grow this space by at least one byte,
+ * possibly moving it (like realloc).  Grabstackblock actually allocates the
+ * part of the block that has been used.
+ */
+
+static void
+growstackblock(int min)
+{
+	char *p;
+	int newlen;
+	char *oldspace;
+	int oldlen;
+	struct stack_block *sp;
+	struct stack_block *oldstackp;
+
+	if (min < stacknleft)
+		min = stacknleft;
+	if ((unsigned int)min >=
+	    INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
+		error("Out of space");
+	min += stacknleft;
+	min += ALIGN(sizeof(struct stack_block));
+	newlen = 512;
+	while (newlen < min)
+		newlen <<= 1;
+	oldspace = stacknxt;
+	oldlen = stacknleft;
+
+	if (stackp != NULL && stacknxt == SPACE(stackp)) {
+		INTOFF;
+		oldstackp = stackp;
+		stackp = oldstackp->prev;
+		sp = ckrealloc((pointer)oldstackp, newlen);
+		sp->prev = stackp;
+		stackp = sp;
+		stacknxt = SPACE(sp);
+		stacknleft = newlen - (stacknxt - (char*)sp);
+		sstrend = stacknxt + stacknleft;
+		INTON;
+	} else {
+		newlen -= ALIGN(sizeof(struct stack_block));
+		p = stalloc(newlen);
+		if (oldlen != 0)
+			memcpy(p, oldspace, oldlen);
+		stunalloc(p);
+	}
+}
+
+
+
+/*
+ * The following routines are somewhat easier to use that the above.
+ * The user declares a variable of type STACKSTR, which may be declared
+ * to be a register.  The macro STARTSTACKSTR initializes things.  Then
+ * the user uses the macro STPUTC to add characters to the string.  In
+ * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
+ * grown as necessary.  When the user is done, she can just leave the
+ * string there and refer to it using stackblock().  Or she can allocate
+ * the space for it using grabstackstr().  If it is necessary to allow
+ * someone else to use the stack temporarily and then continue to grow
+ * the string, the user should use grabstack to allocate the space, and
+ * then call ungrabstr(p) to return to the previous mode of operation.
+ *
+ * USTPUTC is like STPUTC except that it doesn't check for overflow.
+ * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
+ * is space for at least one character.
+ */
+
+static char *
+growstrstackblock(int n, int min)
+{
+	growstackblock(min);
+	return stackblock() + n;
+}
+
+char *
+growstackstr(void)
+{
+	int len;
+
+	len = stackblocksize();
+	return (growstrstackblock(len, 0));
+}
+
+
+/*
+ * Called from CHECKSTRSPACE.
+ */
+
+char *
+makestrspace(int min, char *p)
+{
+	int len;
+
+	len = p - stackblock();
+	return (growstrstackblock(len, min));
+}
+
+
+char *
+stputbin(const char *data, size_t len, char *p)
+{
+	CHECKSTRSPACE(len, p);
+	memcpy(p, data, len);
+	return (p + len);
+}
+
+char *
+stputs(const char *data, char *p)
+{
+	return (stputbin(data, strlen(data), p));
+}
diff --git a/bin/1sh/memalloc.h b/bin/1sh/memalloc.h
new file mode 100644
index 00000000..f3acc03d
--- /dev/null
+++ b/bin/1sh/memalloc.h
@@ -0,0 +1,88 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)memalloc.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/memalloc.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+#include <string.h>
+
+struct stackmark {
+	struct stack_block *stackp;
+	char *stacknxt;
+	int stacknleft;
+};
+
+
+extern char *stacknxt;
+extern int stacknleft;
+extern char *sstrend;
+
+pointer ckmalloc(size_t);
+pointer ckrealloc(pointer, int);
+void ckfree(pointer);
+char *savestr(const char *);
+pointer stalloc(int);
+void stunalloc(pointer);
+char *stsavestr(const char *);
+void setstackmark(struct stackmark *);
+void popstackmark(struct stackmark *);
+char *growstackstr(void);
+char *makestrspace(int, char *);
+char *stputbin(const char *data, size_t len, char *p);
+char *stputs(const char *data, char *p);
+
+
+
+#define stackblock() stacknxt
+#define stackblocksize() stacknleft
+#define grabstackblock(n) stalloc(n)
+#define STARTSTACKSTR(p)	p = stackblock()
+#define STPUTC(c, p)	do { if (p == sstrend) p = growstackstr(); *p++ = (c); } while(0)
+#define CHECKSTRSPACE(n, p)	{ if ((size_t)(sstrend - p) < n) p = makestrspace(n, p); }
+#define USTPUTC(c, p)	(*p++ = (c))
+/*
+ * STACKSTRNUL's use is where we want to be able to turn a stack
+ * (non-sentinel, character counting string) into a C string,
+ * and later pretend the NUL is not there.
+ * Note: Because of STACKSTRNUL's semantics, STACKSTRNUL cannot be used
+ * on a stack that will grabstackstr()ed.
+ */
+#define STACKSTRNUL(p)	(p == sstrend ? (p = growstackstr(), *p = '\0') : (*p = '\0'))
+#define STUNPUTC(p)	(--p)
+#define STTOPC(p)	p[-1]
+#define STADJUST(amount, p)	(p += (amount))
+#define grabstackstr(p)	stalloc((char *)p - stackblock())
+#define ungrabstackstr(s, p)	stunalloc((s))
+#define STPUTBIN(s, len, p)	p = stputbin((s), (len), p)
+#define STPUTS(s, p)	p = stputs((s), p)
diff --git a/bin/1sh/miscbltin.c b/bin/1sh/miscbltin.c
new file mode 100644
index 00000000..66329850
--- /dev/null
+++ b/bin/1sh/miscbltin.c
@@ -0,0 +1,534 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)miscbltin.c	8.4 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/miscbltin.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+/*
+ * Miscellaneous builtins.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#include "options.h"
+#include "var.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "syntax.h"
+#include "trap.h"
+
+#undef eflag
+
+int readcmd(int, char **);
+int umaskcmd(int, char **);
+int ulimitcmd(int, char **);
+
+/*
+ * The read builtin.  The -r option causes backslashes to be treated like
+ * ordinary characters.
+ *
+ * This uses unbuffered input, which may be avoidable in some cases.
+ *
+ * Note that if IFS=' :' then read x y should work so that:
+ * 'a b'	x='a', y='b'
+ * ' a b '	x='a', y='b'
+ * ':b'		x='',  y='b'
+ * ':'		x='',  y=''
+ * '::'		x='',  y=''
+ * ': :'	x='',  y=''
+ * ':::'	x='',  y='::'
+ * ':b c:'	x='',  y='b c:'
+ */
+
+int
+readcmd(int argc __unused, char **argv __unused)
+{
+	char **ap;
+	int backslash;
+	char c;
+	int rflag;
+	char *prompt;
+	const char *ifs;
+	char *p;
+	int startword;
+	int status;
+	int i;
+	int is_ifs;
+	int saveall = 0;
+	ptrdiff_t lastnonifs, lastnonifsws;
+	struct timeval tv;
+	char *tvptr;
+	fd_set ifds;
+	ssize_t nread;
+	int sig;
+
+	rflag = 0;
+	prompt = NULL;
+	tv.tv_sec = -1;
+	tv.tv_usec = 0;
+	while ((i = nextopt("erp:t:")) != '\0') {
+		switch(i) {
+		case 'p':
+			prompt = shoptarg;
+			break;
+		case 'e':
+			break;
+		case 'r':
+			rflag = 1;
+			break;
+		case 't':
+			tv.tv_sec = strtol(shoptarg, &tvptr, 0);
+			if (tvptr == shoptarg)
+				error("timeout value");
+			switch(*tvptr) {
+			case 0:
+			case 's':
+				break;
+			case 'h':
+				tv.tv_sec *= 60;
+				/* FALLTHROUGH */
+			case 'm':
+				tv.tv_sec *= 60;
+				break;
+			default:
+				error("timeout unit");
+			}
+			break;
+		}
+	}
+	if (prompt && isatty(0)) {
+		out2str(prompt);
+		flushall();
+	}
+	if (*(ap = argptr) == NULL)
+		error("arg count");
+	if ((ifs = bltinlookup("IFS", 1)) == NULL)
+		ifs = " \t\n";
+
+	if (tv.tv_sec >= 0) {
+		/*
+		 * Wait for something to become available.
+		 */
+		FD_ZERO(&ifds);
+		FD_SET(0, &ifds);
+		status = select(1, &ifds, NULL, NULL, &tv);
+		/*
+		 * If there's nothing ready, return an error.
+		 */
+		if (status <= 0) {
+			sig = pendingsig;
+			return (128 + (sig != 0 ? sig : SIGALRM));
+		}
+	}
+
+	status = 0;
+	startword = 2;
+	backslash = 0;
+	STARTSTACKSTR(p);
+	lastnonifs = lastnonifsws = -1;
+	for (;;) {
+		nread = read(STDIN_FILENO, &c, 1);
+		if (nread == -1) {
+			if (errno == EINTR) {
+				sig = pendingsig;
+				if (sig == 0)
+					continue;
+				status = 128 + sig;
+				break;
+			}
+			warning("read error: %s", strerror(errno));
+			status = 2;
+			break;
+		} else if (nread != 1) {
+			status = 1;
+			break;
+		}
+		if (c == '\0')
+			continue;
+		CHECKSTRSPACE(1, p);
+		if (backslash) {
+			backslash = 0;
+			if (c != '\n') {
+				startword = 0;
+				lastnonifs = lastnonifsws = p - stackblock();
+				USTPUTC(c, p);
+			}
+			continue;
+		}
+		if (!rflag && c == '\\') {
+			backslash++;
+			continue;
+		}
+		if (c == '\n')
+			break;
+		if (strchr(ifs, c))
+			is_ifs = strchr(" \t\n", c) ? 1 : 2;
+		else
+			is_ifs = 0;
+
+		if (startword != 0) {
+			if (is_ifs == 1) {
+				/* Ignore leading IFS whitespace */
+				if (saveall)
+					USTPUTC(c, p);
+				continue;
+			}
+			if (is_ifs == 2 && startword == 1) {
+				/* Only one non-whitespace IFS per word */
+				startword = 2;
+				if (saveall) {
+					lastnonifsws = p - stackblock();
+					USTPUTC(c, p);
+				}
+				continue;
+			}
+		}
+
+		if (is_ifs == 0) {
+			/* append this character to the current variable */
+			startword = 0;
+			if (saveall)
+				/* Not just a spare terminator */
+				saveall++;
+			lastnonifs = lastnonifsws = p - stackblock();
+			USTPUTC(c, p);
+			continue;
+		}
+
+		/* end of variable... */
+		startword = is_ifs;
+
+		if (ap[1] == NULL) {
+			/* Last variable needs all IFS chars */
+			saveall++;
+			if (is_ifs == 2)
+				lastnonifsws = p - stackblock();
+			USTPUTC(c, p);
+			continue;
+		}
+
+		STACKSTRNUL(p);
+		setvar(*ap, stackblock(), 0);
+		ap++;
+		STARTSTACKSTR(p);
+		lastnonifs = lastnonifsws = -1;
+	}
+	STACKSTRNUL(p);
+
+	/*
+	 * Remove trailing IFS chars: always remove whitespace, don't remove
+	 * non-whitespace unless it was naked
+	 */
+	if (saveall <= 1)
+		lastnonifsws = lastnonifs;
+	stackblock()[lastnonifsws + 1] = '\0';
+	setvar(*ap, stackblock(), 0);
+
+	/* Set any remaining args to "" */
+	while (*++ap != NULL)
+		setvar(*ap, "", 0);
+	return status;
+}
+
+
+
+int
+umaskcmd(int argc __unused, char **argv __unused)
+{
+	char *ap;
+	int mask;
+	int i;
+	int symbolic_mode = 0;
+
+	while ((i = nextopt("S")) != '\0') {
+		symbolic_mode = 1;
+	}
+
+	INTOFF;
+	mask = umask(0);
+	umask(mask);
+	INTON;
+
+	if ((ap = *argptr) == NULL) {
+		if (symbolic_mode) {
+			char u[4], g[4], o[4];
+
+			i = 0;
+			if ((mask & S_IRUSR) == 0)
+				u[i++] = 'r';
+			if ((mask & S_IWUSR) == 0)
+				u[i++] = 'w';
+			if ((mask & S_IXUSR) == 0)
+				u[i++] = 'x';
+			u[i] = '\0';
+
+			i = 0;
+			if ((mask & S_IRGRP) == 0)
+				g[i++] = 'r';
+			if ((mask & S_IWGRP) == 0)
+				g[i++] = 'w';
+			if ((mask & S_IXGRP) == 0)
+				g[i++] = 'x';
+			g[i] = '\0';
+
+			i = 0;
+			if ((mask & S_IROTH) == 0)
+				o[i++] = 'r';
+			if ((mask & S_IWOTH) == 0)
+				o[i++] = 'w';
+			if ((mask & S_IXOTH) == 0)
+				o[i++] = 'x';
+			o[i] = '\0';
+
+			out1fmt("u=%s,g=%s,o=%s\n", u, g, o);
+		} else {
+			out1fmt("%.4o\n", mask);
+		}
+	} else {
+		if (is_digit(*ap)) {
+			mask = 0;
+			do {
+				if (*ap >= '8' || *ap < '0')
+					error("Illegal number: %s", *argptr);
+				mask = (mask << 3) + (*ap - '0');
+			} while (*++ap != '\0');
+			umask(mask);
+		} else {
+			void *set;
+			INTOFF;
+			if ((set = setmode (ap)) == NULL)
+				error("Illegal number: %s", ap);
+
+			mask = getmode (set, ~mask & 0777);
+			umask(~mask & 0777);
+			free(set);
+			INTON;
+		}
+	}
+	return 0;
+}
+
+/*
+ * ulimit builtin
+ *
+ * This code, originally by Doug Gwyn, Doug Kingston, Eric Gisin, and
+ * Michael Rendell was ripped from pdksh 5.0.8 and hacked for use with
+ * ash by J.T. Conklin.
+ *
+ * Public domain.
+ */
+
+struct limits {
+	const char *name;
+	const char *units;
+	int	cmd;
+	short	factor;	/* multiply by to get rlim_{cur,max} values */
+	char	option;
+};
+
+static const struct limits limits[] = {
+#ifdef RLIMIT_CPU
+	{ "cpu time",		"seconds",	RLIMIT_CPU,	   1, 't' },
+#endif
+#ifdef RLIMIT_FSIZE
+	{ "file size",		"512-blocks",	RLIMIT_FSIZE,	 512, 'f' },
+#endif
+#ifdef RLIMIT_DATA
+	{ "data seg size",	"kbytes",	RLIMIT_DATA,	1024, 'd' },
+#endif
+#ifdef RLIMIT_STACK
+	{ "stack size",		"kbytes",	RLIMIT_STACK,	1024, 's' },
+#endif
+#ifdef  RLIMIT_CORE
+	{ "core file size",	"512-blocks",	RLIMIT_CORE,	 512, 'c' },
+#endif
+#ifdef RLIMIT_RSS
+	{ "max memory size",	"kbytes",	RLIMIT_RSS,	1024, 'm' },
+#endif
+#ifdef RLIMIT_MEMLOCK
+	{ "locked memory",	"kbytes",	RLIMIT_MEMLOCK, 1024, 'l' },
+#endif
+#ifdef RLIMIT_NPROC
+	{ "max user processes",	(char *)0,	RLIMIT_NPROC,      1, 'u' },
+#endif
+#ifdef RLIMIT_NOFILE
+	{ "open files",		(char *)0,	RLIMIT_NOFILE,     1, 'n' },
+#endif
+#ifdef RLIMIT_VMEM
+	{ "virtual mem size",	"kbytes",	RLIMIT_VMEM,	1024, 'v' },
+#endif
+#ifdef RLIMIT_SWAP
+	{ "swap limit",		"kbytes",	RLIMIT_SWAP,	1024, 'w' },
+#endif
+#ifdef RLIMIT_SBSIZE
+	{ "socket buffer size",	"bytes",	RLIMIT_SBSIZE,	   1, 'b' },
+#endif
+#ifdef RLIMIT_NPTS
+	{ "pseudo-terminals",	(char *)0,	RLIMIT_NPTS,	   1, 'p' },
+#endif
+#ifdef RLIMIT_KQUEUES
+	{ "kqueues",		(char *)0,	RLIMIT_KQUEUES,	   1, 'k' },
+#endif
+#ifdef RLIMIT_UMTXP
+	{ "umtx shared locks",	(char *)0,	RLIMIT_UMTXP,	   1, 'o' },
+#endif
+	{ (char *) 0,		(char *)0,	0,		   0, '\0' }
+};
+
+enum limithow { SOFT = 0x1, HARD = 0x2 };
+
+static void
+printlimit(enum limithow how, const struct rlimit *limit,
+    const struct limits *l)
+{
+	rlim_t val = 0;
+
+	if (how & SOFT)
+		val = limit->rlim_cur;
+	else if (how & HARD)
+		val = limit->rlim_max;
+	if (val == RLIM_INFINITY)
+		out1str("unlimited\n");
+	else
+	{
+		val /= l->factor;
+		out1fmt("%jd\n", (intmax_t)val);
+	}
+}
+
+int
+ulimitcmd(int argc __unused, char **argv __unused)
+{
+	rlim_t val = 0;
+	enum limithow how = SOFT | HARD;
+	const struct limits	*l;
+	int		set, all = 0;
+	int		optc, what;
+	struct rlimit	limit;
+
+	what = 'f';
+	while ((optc = nextopt("HSatfdsmcnuvlbpwko")) != '\0')
+		switch (optc) {
+		case 'H':
+			how = HARD;
+			break;
+		case 'S':
+			how = SOFT;
+			break;
+		case 'a':
+			all = 1;
+			break;
+		default:
+			what = optc;
+		}
+
+	for (l = limits; l->name && l->option != what; l++)
+		;
+	if (!l->name)
+		error("internal error (%c)", what);
+
+	set = *argptr ? 1 : 0;
+	if (set) {
+		char *p = *argptr;
+
+		if (all || argptr[1])
+			error("too many arguments");
+		if (strcmp(p, "unlimited") == 0)
+			val = RLIM_INFINITY;
+		else {
+			char *end;
+			uintmax_t uval;
+
+			if (*p < '0' || *p > '9')
+				error("bad number");
+			errno = 0;
+			uval = strtoumax(p, &end, 10);
+			if (errno != 0 || *end != '\0')
+				error("bad number");
+			if (uval > UINTMAX_MAX / l->factor)
+				error("bad number");
+			uval *= l->factor;
+			val = (rlim_t)uval;
+			if (val < 0 || (uintmax_t)val != uval ||
+			    val == RLIM_INFINITY)
+				error("bad number");
+		}
+	}
+	if (all) {
+		for (l = limits; l->name; l++) {
+			char optbuf[40];
+			if (getrlimit(l->cmd, &limit) < 0)
+				error("can't get limit: %s", strerror(errno));
+
+			if (l->units)
+				snprintf(optbuf, sizeof(optbuf),
+					"(%s, -%c) ", l->units, l->option);
+			else
+				snprintf(optbuf, sizeof(optbuf),
+					"(-%c) ", l->option);
+			out1fmt("%-18s %18s ", l->name, optbuf);
+			printlimit(how, &limit, l);
+		}
+		return 0;
+	}
+
+	if (getrlimit(l->cmd, &limit) < 0)
+		error("can't get limit: %s", strerror(errno));
+	if (set) {
+		if (how & SOFT)
+			limit.rlim_cur = val;
+		if (how & HARD)
+			limit.rlim_max = val;
+		if (setrlimit(l->cmd, &limit) < 0)
+			error("bad limit: %s", strerror(errno));
+	} else
+		printlimit(how, &limit, l);
+	return 0;
+}
diff --git a/bin/1sh/mkbuiltins b/bin/1sh/mkbuiltins
new file mode 100755
index 00000000..cbcf0ec1
--- /dev/null
+++ b/bin/1sh/mkbuiltins
@@ -0,0 +1,137 @@
+#!/bin/sh -
+
+#-
+# Copyright (c) 1991, 1993
+#	The Regents of the University of California.  All rights reserved.
+#
+# This code is derived from software contributed to Berkeley by
+# Kenneth Almquist.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. Neither the name of the University nor the names of its contributors
+#    may be used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+#	@(#)mkbuiltins	8.2 (Berkeley) 5/4/95
+# $FreeBSD: releng/12.1/bin/sh/mkbuiltins 328934 2018-02-06 15:41:35Z arichardson $
+
+temp=`mktemp`
+havehist=1
+if [ "X$1" = "X-h" ]; then
+	havehist=0
+	shift
+fi
+srcdir=$1
+havejobs=0
+if grep '^#define[	 ]*JOBS[	 ]*1' $srcdir/shell.h > /dev/null
+then	havejobs=1
+fi
+exec > builtins.c
+cat <<\!
+/*
+ * This file was generated by the mkbuiltins program.
+ */
+
+#include <stdlib.h>
+#include "shell.h"
+#include "builtins.h"
+
+!
+awk '/^[^#]/ {if(('$havejobs' || $2 != "-j") && ('$havehist' || $2 != "-h")) \
+    print $0}' $srcdir/builtins.def | sed 's/-[hj]//' > $temp
+echo 'int (*const builtinfunc[])(int, char **) = {'
+awk '/^[^#]/ {	printf "\t%s,\n", $1}' $temp
+echo '};
+
+const unsigned char builtincmd[] = {'
+awk '{	for (i = 2 ; i <= NF ; i++) {
+		if ($i == "-s") {
+			spc = 1;
+		} else if ($i == "-n") {
+			# Handled later for builtins.h
+			continue
+		} else {
+			printf "\t\"\\%03o\\%03o%s\"\n", length($i), (spc ? 128 : 0) + NR-1, $i
+			spc = 0;
+		}
+	}}' $temp
+echo '};'
+
+exec > builtins.h
+cat <<\!
+/*
+ * This file was generated by the mkbuiltins program.
+ */
+
+#include <sys/cdefs.h>
+!
+tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ < $temp |
+	awk '{	printf "#define %s %d\n", $1, NR-1}'
+echo '
+#define BUILTIN_SPECIAL 0x80
+
+extern int (*const builtinfunc[])(int, char **);
+extern const unsigned char builtincmd[];
+'
+awk '{	printf "int %s(int, char **);\n", $1}' $temp
+
+# Build safe_builtin_always()
+cat <<EOF
+
+static inline int
+safe_builtin_always(int idx)
+{
+EOF
+awk '
+BEGIN { printed = 0 }
+{
+	for (i = 2 ; i <= NF ; i++) {
+		if ($i == "-s") {
+			continue
+		} else if ($i == "-n") {
+			nofork = 1;
+		} else {
+			if (nofork == 0) {
+				continue
+			}
+			if (printed == 1) {
+				printf " || \n\t    "
+			} else {
+				printf "\tif ("
+			}
+			printf "idx == " toupper($1)
+			printed = 1
+			nofork = 0;
+			# Only need to check each once
+			break
+		}
+	}
+}' $temp
+
+cat << EOF
+)
+		return (1);
+	return(0);
+}
+EOF
+
+rm -f $temp
diff --git a/bin/1sh/mknodes.c b/bin/1sh/mknodes.c
new file mode 100644
index 00000000..9ec4dfbd
--- /dev/null
+++ b/bin/1sh/mknodes.c
@@ -0,0 +1,461 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if 0
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1991, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)mknodes.c	8.2 (Berkeley) 5/4/95";
+#endif /* not lint */
+#endif
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/mknodes.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+/*
+ * This program reads the nodetypes file and nodes.c.pat file.  It generates
+ * the files nodes.h and nodes.c.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#define MAXTYPES 50		/* max number of node types */
+#define MAXFIELDS 20		/* max fields in a structure */
+#define BUFLEN 100		/* size of character buffers */
+
+/* field types */
+#define T_NODE 1		/* union node *field */
+#define T_NODELIST 2		/* struct nodelist *field */
+#define T_STRING 3
+#define T_INT 4			/* int field */
+#define T_OTHER 5		/* other */
+#define T_TEMP 6		/* don't copy this field */
+
+
+struct field {			/* a structure field */
+	char *name;		/* name of field */
+	int type;			/* type of field */
+	char *decl;		/* declaration of field */
+};
+
+
+struct str {			/* struct representing a node structure */
+	char *tag;		/* structure tag */
+	int nfields;		/* number of fields in the structure */
+	struct field field[MAXFIELDS];	/* the fields of the structure */
+	int done;			/* set if fully parsed */
+};
+
+
+static int ntypes;			/* number of node types */
+static char *nodename[MAXTYPES];	/* names of the nodes */
+static struct str *nodestr[MAXTYPES];	/* type of structure used by the node */
+static int nstr;			/* number of structures */
+static struct str str[MAXTYPES];	/* the structures */
+static struct str *curstr;		/* current structure */
+static char line[1024];
+static int linno;
+static char *linep;
+
+static void parsenode(void);
+static void parsefield(void);
+static void output(char *);
+static void outsizes(FILE *);
+static void outfunc(FILE *, int);
+static void indent(int, FILE *);
+static int nextfield(char *);
+static void skipbl(void);
+static int readline(FILE *);
+static void error(const char *, ...) __attribute__((format(printf, 1, 2))) __attribute__((noreturn));
+static char *savestr(const char *);
+
+
+int
+main(int argc, char *argv[])
+{
+	FILE *infp;
+
+	if (argc != 3)
+		error("usage: mknodes file");
+	if ((infp = fopen(argv[1], "r")) == NULL)
+		error("Can't open %s: %s", argv[1], strerror(errno));
+	while (readline(infp)) {
+		if (line[0] == ' ' || line[0] == '\t')
+			parsefield();
+		else if (line[0] != '\0')
+			parsenode();
+	}
+	fclose(infp);
+	output(argv[2]);
+	exit(0);
+}
+
+
+
+static void
+parsenode(void)
+{
+	char name[BUFLEN];
+	char tag[BUFLEN];
+	struct str *sp;
+
+	if (curstr && curstr->nfields > 0)
+		curstr->done = 1;
+	nextfield(name);
+	if (! nextfield(tag))
+		error("Tag expected");
+	if (*linep != '\0')
+		error("Garbage at end of line");
+	nodename[ntypes] = savestr(name);
+	for (sp = str ; sp < str + nstr ; sp++) {
+		if (strcmp(sp->tag, tag) == 0)
+			break;
+	}
+	if (sp >= str + nstr) {
+		sp->tag = savestr(tag);
+		sp->nfields = 0;
+		curstr = sp;
+		nstr++;
+	}
+	nodestr[ntypes] = sp;
+	ntypes++;
+}
+
+
+static void
+parsefield(void)
+{
+	char name[BUFLEN];
+	char type[BUFLEN];
+	char decl[2 * BUFLEN];
+	struct field *fp;
+
+	if (curstr == NULL || curstr->done)
+		error("No current structure to add field to");
+	if (! nextfield(name))
+		error("No field name");
+	if (! nextfield(type))
+		error("No field type");
+	fp = &curstr->field[curstr->nfields];
+	fp->name = savestr(name);
+	if (strcmp(type, "nodeptr") == 0) {
+		fp->type = T_NODE;
+		sprintf(decl, "union node *%s", name);
+	} else if (strcmp(type, "nodelist") == 0) {
+		fp->type = T_NODELIST;
+		sprintf(decl, "struct nodelist *%s", name);
+	} else if (strcmp(type, "string") == 0) {
+		fp->type = T_STRING;
+		sprintf(decl, "char *%s", name);
+	} else if (strcmp(type, "int") == 0) {
+		fp->type = T_INT;
+		sprintf(decl, "int %s", name);
+	} else if (strcmp(type, "other") == 0) {
+		fp->type = T_OTHER;
+	} else if (strcmp(type, "temp") == 0) {
+		fp->type = T_TEMP;
+	} else {
+		error("Unknown type %s", type);
+	}
+	if (fp->type == T_OTHER || fp->type == T_TEMP) {
+		skipbl();
+		fp->decl = savestr(linep);
+	} else {
+		if (*linep)
+			error("Garbage at end of line");
+		fp->decl = savestr(decl);
+	}
+	curstr->nfields++;
+}
+
+
+static const char writer[] = "\
+/*\n\
+ * This file was generated by the mknodes program.\n\
+ */\n\
+\n";
+
+static void
+output(char *file)
+{
+	FILE *hfile;
+	FILE *cfile;
+	FILE *patfile;
+	int i;
+	struct str *sp;
+	struct field *fp;
+	char *p;
+
+	if ((patfile = fopen(file, "r")) == NULL)
+		error("Can't open %s: %s", file, strerror(errno));
+	if ((hfile = fopen("nodes.h", "w")) == NULL)
+		error("Can't create nodes.h: %s", strerror(errno));
+	if ((cfile = fopen("nodes.c", "w")) == NULL)
+		error("Can't create nodes.c");
+	fputs(writer, hfile);
+	for (i = 0 ; i < ntypes ; i++)
+		fprintf(hfile, "#define %s %d\n", nodename[i], i);
+	fputs("\n\n\n", hfile);
+	for (sp = str ; sp < &str[nstr] ; sp++) {
+		fprintf(hfile, "struct %s {\n", sp->tag);
+		for (i = sp->nfields, fp = sp->field ; --i >= 0 ; fp++) {
+			fprintf(hfile, "      %s;\n", fp->decl);
+		}
+		fputs("};\n\n\n", hfile);
+	}
+	fputs("union node {\n", hfile);
+	fprintf(hfile, "      int type;\n");
+	for (sp = str ; sp < &str[nstr] ; sp++) {
+		fprintf(hfile, "      struct %s %s;\n", sp->tag, sp->tag);
+	}
+	fputs("};\n\n\n", hfile);
+	fputs("struct nodelist {\n", hfile);
+	fputs("\tstruct nodelist *next;\n", hfile);
+	fputs("\tunion node *n;\n", hfile);
+	fputs("};\n\n\n", hfile);
+	fputs("struct funcdef;\n", hfile);
+	fputs("struct funcdef *copyfunc(union node *);\n", hfile);
+	fputs("union node *getfuncnode(struct funcdef *);\n", hfile);
+	fputs("void reffunc(struct funcdef *);\n", hfile);
+	fputs("void unreffunc(struct funcdef *);\n", hfile);
+	if (ferror(hfile))
+		error("Can't write to nodes.h");
+	if (fclose(hfile))
+		error("Can't close nodes.h");
+
+	fputs(writer, cfile);
+	while (fgets(line, sizeof line, patfile) != NULL) {
+		for (p = line ; *p == ' ' || *p == '\t' ; p++);
+		if (strcmp(p, "%SIZES\n") == 0)
+			outsizes(cfile);
+		else if (strcmp(p, "%CALCSIZE\n") == 0)
+			outfunc(cfile, 1);
+		else if (strcmp(p, "%COPY\n") == 0)
+			outfunc(cfile, 0);
+		else
+			fputs(line, cfile);
+	}
+	fclose(patfile);
+	if (ferror(cfile))
+		error("Can't write to nodes.c");
+	if (fclose(cfile))
+		error("Can't close nodes.c");
+}
+
+
+
+static void
+outsizes(FILE *cfile)
+{
+	int i;
+
+	fprintf(cfile, "static const short nodesize[%d] = {\n", ntypes);
+	for (i = 0 ; i < ntypes ; i++) {
+		fprintf(cfile, "      ALIGN(sizeof (struct %s)),\n", nodestr[i]->tag);
+	}
+	fprintf(cfile, "};\n");
+}
+
+
+static void
+outfunc(FILE *cfile, int calcsize)
+{
+	struct str *sp;
+	struct field *fp;
+	int i;
+
+	fputs("      if (n == NULL)\n", cfile);
+	if (calcsize)
+		fputs("	    return;\n", cfile);
+	else
+		fputs("	    return NULL;\n", cfile);
+	if (calcsize)
+		fputs("      result->blocksize += nodesize[n->type];\n", cfile);
+	else {
+		fputs("      new = state->block;\n", cfile);
+		fputs("      state->block = (char *)state->block + nodesize[n->type];\n", cfile);
+	}
+	fputs("      switch (n->type) {\n", cfile);
+	for (sp = str ; sp < &str[nstr] ; sp++) {
+		for (i = 0 ; i < ntypes ; i++) {
+			if (nodestr[i] == sp)
+				fprintf(cfile, "      case %s:\n", nodename[i]);
+		}
+		for (i = sp->nfields ; --i >= 1 ; ) {
+			fp = &sp->field[i];
+			switch (fp->type) {
+			case T_NODE:
+				if (calcsize) {
+					indent(12, cfile);
+					fprintf(cfile, "calcsize(n->%s.%s, result);\n",
+						sp->tag, fp->name);
+				} else {
+					indent(12, cfile);
+					fprintf(cfile, "new->%s.%s = copynode(n->%s.%s, state);\n",
+						sp->tag, fp->name, sp->tag, fp->name);
+				}
+				break;
+			case T_NODELIST:
+				if (calcsize) {
+					indent(12, cfile);
+					fprintf(cfile, "sizenodelist(n->%s.%s, result);\n",
+						sp->tag, fp->name);
+				} else {
+					indent(12, cfile);
+					fprintf(cfile, "new->%s.%s = copynodelist(n->%s.%s, state);\n",
+						sp->tag, fp->name, sp->tag, fp->name);
+				}
+				break;
+			case T_STRING:
+				if (calcsize) {
+					indent(12, cfile);
+					fprintf(cfile, "result->stringsize += strlen(n->%s.%s) + 1;\n",
+						sp->tag, fp->name);
+				} else {
+					indent(12, cfile);
+					fprintf(cfile, "new->%s.%s = nodesavestr(n->%s.%s, state);\n",
+						sp->tag, fp->name, sp->tag, fp->name);
+				}
+				break;
+			case T_INT:
+			case T_OTHER:
+				if (! calcsize) {
+					indent(12, cfile);
+					fprintf(cfile, "new->%s.%s = n->%s.%s;\n",
+						sp->tag, fp->name, sp->tag, fp->name);
+				}
+				break;
+			}
+		}
+		indent(12, cfile);
+		fputs("break;\n", cfile);
+	}
+	fputs("      };\n", cfile);
+	if (! calcsize)
+		fputs("      new->type = n->type;\n", cfile);
+}
+
+
+static void
+indent(int amount, FILE *fp)
+{
+	while (amount >= 8) {
+		putc('\t', fp);
+		amount -= 8;
+	}
+	while (--amount >= 0) {
+		putc(' ', fp);
+	}
+}
+
+
+static int
+nextfield(char *buf)
+{
+	char *p, *q;
+
+	p = linep;
+	while (*p == ' ' || *p == '\t')
+		p++;
+	q = buf;
+	while (*p != ' ' && *p != '\t' && *p != '\0')
+		*q++ = *p++;
+	*q = '\0';
+	linep = p;
+	return (q > buf);
+}
+
+
+static void
+skipbl(void)
+{
+	while (*linep == ' ' || *linep == '\t')
+		linep++;
+}
+
+
+static int
+readline(FILE *infp)
+{
+	char *p;
+
+	if (fgets(line, 1024, infp) == NULL)
+		return 0;
+	for (p = line ; *p != '#' && *p != '\n' && *p != '\0' ; p++);
+	while (p > line && (p[-1] == ' ' || p[-1] == '\t'))
+		p--;
+	*p = '\0';
+	linep = line;
+	linno++;
+	if (p - line > BUFLEN)
+		error("Line too long");
+	return 1;
+}
+
+
+
+static void
+error(const char *msg, ...)
+{
+	va_list va;
+	va_start(va, msg);
+
+	(void) fprintf(stderr, "line %d: ", linno);
+	(void) vfprintf(stderr, msg, va);
+	(void) fputc('\n', stderr);
+
+	va_end(va);
+
+	exit(2);
+}
+
+
+
+static char *
+savestr(const char *s)
+{
+	char *p;
+
+	if ((p = malloc(strlen(s) + 1)) == NULL)
+		error("Out of space");
+	(void) strcpy(p, s);
+	return p;
+}
diff --git a/bin/1sh/mksyntax.c b/bin/1sh/mksyntax.c
new file mode 100644
index 00000000..b61378a9
--- /dev/null
+++ b/bin/1sh/mksyntax.c
@@ -0,0 +1,332 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if 0
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1991, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)mksyntax.c	8.2 (Berkeley) 5/4/95";
+#endif /* not lint */
+#endif
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/mksyntax.c 334008 2018-05-21 21:52:48Z jilles $ */
+
+/*
+ * This program creates syntax.h and syntax.c.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "parser.h"
+
+
+struct synclass {
+	const char *name;
+	const char *comment;
+};
+
+/* Syntax classes */
+static const struct synclass synclass[] = {
+	{ "CWORD",	"character is nothing special" },
+	{ "CNL",	"newline character" },
+	{ "CQNL",	"newline character in quotes" },
+	{ "CBACK",	"a backslash character" },
+	{ "CSBACK",	"a backslash character in single quotes" },
+	{ "CSQUOTE",	"single quote" },
+	{ "CDQUOTE",	"double quote" },
+	{ "CENDQUOTE",	"a terminating quote" },
+	{ "CBQUOTE",	"backwards single quote" },
+	{ "CVAR",	"a dollar sign" },
+	{ "CENDVAR",	"a '}' character" },
+	{ "CLP",	"a left paren in arithmetic" },
+	{ "CRP",	"a right paren in arithmetic" },
+	{ "CEOF",	"end of file" },
+	{ "CCTL",	"like CWORD, except it must be escaped" },
+	{ "CSPCL",	"these terminate a word" },
+	{ "CIGN",       "character should be ignored" },
+	{ NULL,		NULL }
+};
+
+
+/*
+ * Syntax classes for is_ functions.  Warning:  if you add new classes
+ * you may have to change the definition of the is_in_name macro.
+ */
+static const struct synclass is_entry[] = {
+	{ "ISDIGIT",	"a digit" },
+	{ "ISUPPER",	"an upper case letter" },
+	{ "ISLOWER",	"a lower case letter" },
+	{ "ISUNDER",	"an underscore" },
+	{ "ISSPECL",	"the name of a special parameter" },
+	{ NULL, 	NULL }
+};
+
+static const char writer[] = "\
+/*\n\
+ * This file was generated by the mksyntax program.\n\
+ */\n\
+\n";
+
+
+static FILE *cfile;
+static FILE *hfile;
+
+static void add_default(void);
+static void finish(void);
+static void init(const char *);
+static void add(const char *, const char *);
+static void output_type_macros(void);
+
+int
+main(int argc __unused, char **argv __unused)
+{
+	int i;
+	char buf[80];
+	int pos;
+
+	/* Create output files */
+	if ((cfile = fopen("syntax.c", "w")) == NULL) {
+		perror("syntax.c");
+		exit(2);
+	}
+	if ((hfile = fopen("syntax.h", "w")) == NULL) {
+		perror("syntax.h");
+		exit(2);
+	}
+	fputs(writer, hfile);
+	fputs(writer, cfile);
+
+	fputs("#include <sys/cdefs.h>\n", hfile);
+	fputs("#include <limits.h>\n\n", hfile);
+
+	/* Generate the #define statements in the header file */
+	fputs("/* Syntax classes */\n", hfile);
+	for (i = 0 ; synclass[i].name ; i++) {
+		sprintf(buf, "#define %s %d", synclass[i].name, i);
+		fputs(buf, hfile);
+		for (pos = strlen(buf) ; pos < 32 ; pos = (pos + 8) & ~07)
+			putc('\t', hfile);
+		fprintf(hfile, "/* %s */\n", synclass[i].comment);
+	}
+	putc('\n', hfile);
+	fputs("/* Syntax classes for is_ functions */\n", hfile);
+	for (i = 0 ; is_entry[i].name ; i++) {
+		sprintf(buf, "#define %s %#o", is_entry[i].name, 1 << i);
+		fputs(buf, hfile);
+		for (pos = strlen(buf) ; pos < 32 ; pos = (pos + 8) & ~07)
+			putc('\t', hfile);
+		fprintf(hfile, "/* %s */\n", is_entry[i].comment);
+	}
+	putc('\n', hfile);
+	fputs("#define SYNBASE (1 - CHAR_MIN)\n", hfile);
+	fputs("#define PEOF -SYNBASE\n\n", hfile);
+	putc('\n', hfile);
+	fputs("#define BASESYNTAX (basesyntax + SYNBASE)\n", hfile);
+	fputs("#define DQSYNTAX (dqsyntax + SYNBASE)\n", hfile);
+	fputs("#define SQSYNTAX (sqsyntax + SYNBASE)\n", hfile);
+	fputs("#define ARISYNTAX (arisyntax + SYNBASE)\n", hfile);
+	putc('\n', hfile);
+	output_type_macros();		/* is_digit, etc. */
+	putc('\n', hfile);
+
+	/* Generate the syntax tables. */
+	fputs("#include \"parser.h\"\n", cfile);
+	fputs("#include \"shell.h\"\n", cfile);
+	fputs("#include \"syntax.h\"\n\n", cfile);
+
+	fputs("/* syntax table used when not in quotes */\n", cfile);
+	init("basesyntax");
+	add_default();
+	add("\n", "CNL");
+	add("\\", "CBACK");
+	add("'", "CSQUOTE");
+	add("\"", "CDQUOTE");
+	add("`", "CBQUOTE");
+	add("$", "CVAR");
+	add("}", "CENDVAR");
+	add("<>();&| \t", "CSPCL");
+	finish();
+
+	fputs("\n/* syntax table used when in double quotes */\n", cfile);
+	init("dqsyntax");
+	add_default();
+	add("\n", "CQNL");
+	add("\\", "CBACK");
+	add("\"", "CENDQUOTE");
+	add("`", "CBQUOTE");
+	add("$", "CVAR");
+	add("}", "CENDVAR");
+	/* ':/' for tilde expansion, '-^]' for [a\-x] pattern ranges */
+	add("!*?[]=~:/-^", "CCTL");
+	finish();
+
+	fputs("\n/* syntax table used when in single quotes */\n", cfile);
+	init("sqsyntax");
+	add_default();
+	add("\n", "CQNL");
+	add("\\", "CSBACK");
+	add("'", "CENDQUOTE");
+	/* ':/' for tilde expansion, '-^]' for [a\-x] pattern ranges */
+	add("!*?[]=~:/-^", "CCTL");
+	finish();
+
+	fputs("\n/* syntax table used when in arithmetic */\n", cfile);
+	init("arisyntax");
+	add_default();
+	add("\n", "CQNL");
+	add("\\", "CBACK");
+	add("`", "CBQUOTE");
+	add("\"", "CIGN");
+	add("$", "CVAR");
+	add("}", "CENDVAR");
+	add("(", "CLP");
+	add(")", "CRP");
+	finish();
+
+	fputs("\n/* character classification table */\n", cfile);
+	init("is_type");
+	add("0123456789", "ISDIGIT");
+	add("abcdefghijklmnopqrstuvwxyz", "ISLOWER");
+	add("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "ISUPPER");
+	add("_", "ISUNDER");
+	add("#?$!-*@", "ISSPECL");
+	finish();
+
+	exit(0);
+}
+
+
+/*
+ * Output the header and declaration of a syntax table.
+ */
+
+static void
+init(const char *name)
+{
+	fprintf(hfile, "extern const char %s[];\n", name);
+	fprintf(cfile, "const char %s[SYNBASE + CHAR_MAX + 1] = {\n", name);
+}
+
+
+static void
+add_one(const char *key, const char *type)
+{
+	fprintf(cfile, "\t[SYNBASE + %s] = %s,\n", key, type);
+}
+
+
+/*
+ * Add default values to the syntax table.
+ */
+
+static void
+add_default(void)
+{
+	add_one("PEOF",                "CEOF");
+	add_one("CTLESC",              "CCTL");
+	add_one("CTLVAR",              "CCTL");
+	add_one("CTLENDVAR",           "CCTL");
+	add_one("CTLBACKQ",            "CCTL");
+	add_one("CTLBACKQ + CTLQUOTE", "CCTL");
+	add_one("CTLARI",              "CCTL");
+	add_one("CTLENDARI",           "CCTL");
+	add_one("CTLQUOTEMARK",        "CCTL");
+	add_one("CTLQUOTEEND",         "CCTL");
+}
+
+
+/*
+ * Output the footer of a syntax table.
+ */
+
+static void
+finish(void)
+{
+	fputs("};\n", cfile);
+}
+
+
+/*
+ * Add entries to the syntax table.
+ */
+
+static void
+add(const char *p, const char *type)
+{
+	for (; *p; ++p) {
+		char c = *p;
+		switch (c) {
+		case '\t': c = 't';  break;
+		case '\n': c = 'n';  break;
+		case '\'': c = '\''; break;
+		case '\\': c = '\\'; break;
+
+		default:
+			fprintf(cfile, "\t[SYNBASE + '%c'] = %s,\n", c, type);
+			continue;
+		}
+		fprintf(cfile, "\t[SYNBASE + '\\%c'] = %s,\n", c, type);
+	}
+}
+
+
+/*
+ * Output character classification macros (e.g. is_digit).  If digits are
+ * contiguous, we can test for them quickly.
+ */
+
+static const char *macro[] = {
+	"#define is_digit(c)\t((unsigned int)((c) - '0') <= 9)",
+	"#define is_eof(c)\t((c) == PEOF)",
+	"#define is_alpha(c)\t((is_type+SYNBASE)[(int)c] & (ISUPPER|ISLOWER))",
+	"#define is_name(c)\t((is_type+SYNBASE)[(int)c] & (ISUPPER|ISLOWER|ISUNDER))",
+	"#define is_in_name(c)\t((is_type+SYNBASE)[(int)c] & (ISUPPER|ISLOWER|ISUNDER|ISDIGIT))",
+	"#define is_special(c)\t((is_type+SYNBASE)[(int)c] & (ISSPECL|ISDIGIT))",
+	"#define digit_val(c)\t((c) - '0')",
+	NULL
+};
+
+static void
+output_type_macros(void)
+{
+	const char **pp;
+
+	for (pp = macro ; *pp ; pp++)
+		fprintf(hfile, "%s\n", *pp);
+}
diff --git a/bin/1sh/mktokens b/bin/1sh/mktokens
new file mode 100644
index 00000000..f0d80cc5
--- /dev/null
+++ b/bin/1sh/mktokens
@@ -0,0 +1,93 @@
+#!/bin/sh -
+
+#-
+# Copyright (c) 1991, 1993
+#	The Regents of the University of California.  All rights reserved.
+#
+# This code is derived from software contributed to Berkeley by
+# Kenneth Almquist.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. Neither the name of the University nor the names of its contributors
+#    may be used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+#	@(#)mktokens	8.1 (Berkeley) 5/31/93
+# $FreeBSD: releng/12.1/bin/sh/mktokens 328934 2018-02-06 15:41:35Z arichardson $
+
+# The following is a list of tokens.  The second column is nonzero if the
+# token marks the end of a list.  The third column is the name to print in
+# error messages.
+
+temp=`mktemp`
+cat > $temp <<\!
+TEOF	1	end of file
+TNL	0	newline
+TSEMI	0	";"
+TBACKGND 0	"&"
+TAND	0	"&&"
+TOR	0	"||"
+TPIPE	0	"|"
+TLP	0	"("
+TRP	1	")"
+TENDCASE 1	";;"
+TFALLTHRU 1	";&"
+TREDIR	0	redirection
+TWORD	0	word
+TIF	0	"if"
+TTHEN	1	"then"
+TELSE	1	"else"
+TELIF	1	"elif"
+TFI	1	"fi"
+TWHILE	0	"while"
+TUNTIL	0	"until"
+TFOR	0	"for"
+TDO	1	"do"
+TDONE	1	"done"
+TBEGIN	0	"{"
+TEND	1	"}"
+TCASE	0	"case"
+TESAC	1	"esac"
+TNOT	0	"!"
+!
+nl=`wc -l $temp`
+exec > token.h
+awk '{print "#define " $1 " " NR-1}' $temp
+echo '
+/* Array indicating which tokens mark the end of a list */
+static const char tokendlist[] = {'
+awk '{print "\t" $2 ","}' $temp
+echo '};
+
+static const char *const tokname[] = {'
+sed -e 's/"/\\"/g' \
+    -e 's/[^	 ]*[	 ][	 ]*[^	 ]*[	 ][	 ]*\(.*\)/	"\1",/' \
+    $temp
+echo '};
+'
+sed 's/"//g' $temp | awk '
+/TIF/{print "#define KWDOFFSET " NR-1; print ""; print "const char *const parsekwd[] = {"}
+/TIF/,/neverfound/{print "	\"" $3 "\","}'
+echo '	0
+};'
+
+rm $temp
diff --git a/bin/1sh/myhistedit.h b/bin/1sh/myhistedit.h
new file mode 100644
index 00000000..e9a2be2c
--- /dev/null
+++ b/bin/1sh/myhistedit.h
@@ -0,0 +1,45 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)myhistedit.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/myhistedit.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+#include <histedit.h>
+
+extern History *hist;
+extern EditLine *el;
+extern int displayhist;
+
+void histedit(void);
+void sethistfile(const char *);
+void sethistsize(const char *);
+void setterm(const char *);
+
diff --git a/bin/1sh/mystring.c b/bin/1sh/mystring.c
new file mode 100644
index 00000000..ddeea4c1
--- /dev/null
+++ b/bin/1sh/mystring.c
@@ -0,0 +1,100 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/mystring.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+/*
+ * String functions.
+ *
+ *	equal(s1, s2)		Return true if strings are equal.
+ *	number(s)		Convert a string of digits to an integer.
+ *	is_number(s)		Return true if s is a string of digits.
+ */
+
+#include <stdlib.h>
+#include "shell.h"
+#include "syntax.h"
+#include "error.h"
+#include "mystring.h"
+
+
+char nullstr[1];		/* zero length string */
+
+/*
+ * equal - #defined in mystring.h
+ */
+
+
+/*
+ * Convert a string of digits to an integer, printing an error message on
+ * failure.
+ */
+
+int
+number(const char *s)
+{
+	if (! is_number(s))
+		error("Illegal number: %s", s);
+	return atoi(s);
+}
+
+
+
+/*
+ * Check for a valid number.  This should be elsewhere.
+ */
+
+int
+is_number(const char *p)
+{
+	const char *q;
+
+	if (*p == '\0')
+		return 0;
+	while (*p == '0')
+		p++;
+	for (q = p; *q != '\0'; q++)
+		if (! is_digit(*q))
+			return 0;
+	if (q - p > 10 ||
+	    (q - p == 10 && memcmp(p, "2147483647", 10) > 0))
+		return 0;
+	return 1;
+}
diff --git a/bin/1sh/mystring.h b/bin/1sh/mystring.h
new file mode 100644
index 00000000..9f4960e5
--- /dev/null
+++ b/bin/1sh/mystring.h
@@ -0,0 +1,43 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)mystring.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/mystring.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+#include <string.h>
+
+int number(const char *);
+int is_number(const char *);
+
+#define equal(s1, s2)	(strcmp(s1, s2) == 0)
diff --git a/bin/1sh/nodes.c.pat b/bin/1sh/nodes.c.pat
new file mode 100644
index 00000000..b687b570
--- /dev/null
+++ b/bin/1sh/nodes.c.pat
@@ -0,0 +1,193 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)nodes.c.pat	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/nodes.c.pat 314436 2017-02-28 23:42:47Z imp $
+ */
+
+#include <sys/param.h>
+#include <stdlib.h>
+#include <stddef.h>
+/*
+ * Routine for dealing with parsed shell commands.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "memalloc.h"
+#include "mystring.h"
+
+
+struct nodesize {
+	int     blocksize;	/* size of structures in function */
+	int     stringsize;	/* size of strings in node */
+};
+
+struct nodecopystate {
+	pointer block;		/* block to allocate function from */
+	char   *string;		/* block to allocate strings from */
+};
+
+%SIZES
+
+
+static void calcsize(union node *, struct nodesize *);
+static void sizenodelist(struct nodelist *, struct nodesize *);
+static union node *copynode(union node *, struct nodecopystate *);
+static struct nodelist *copynodelist(struct nodelist *, struct nodecopystate *);
+static char *nodesavestr(const char *, struct nodecopystate *);
+
+
+struct funcdef {
+	unsigned int refcount;
+	union node n;
+};
+
+/*
+ * Make a copy of a parse tree.
+ */
+
+struct funcdef *
+copyfunc(union node *n)
+{
+	struct nodesize sz;
+	struct nodecopystate st;
+	struct funcdef *fn;
+
+	if (n == NULL)
+		return NULL;
+	sz.blocksize = offsetof(struct funcdef, n);
+	sz.stringsize = 0;
+	calcsize(n, &sz);
+	fn = ckmalloc(sz.blocksize + sz.stringsize);
+	fn->refcount = 1;
+	st.block = (char *)fn + offsetof(struct funcdef, n);
+	st.string = (char *)fn + sz.blocksize;
+	copynode(n, &st);
+	return fn;
+}
+
+
+union node *
+getfuncnode(struct funcdef *fn)
+{
+	return fn == NULL ? NULL : &fn->n;
+}
+
+
+static void
+calcsize(union node *n, struct nodesize *result)
+{
+	%CALCSIZE
+}
+
+
+
+static void
+sizenodelist(struct nodelist *lp, struct nodesize *result)
+{
+	while (lp) {
+		result->blocksize += ALIGN(sizeof(struct nodelist));
+		calcsize(lp->n, result);
+		lp = lp->next;
+	}
+}
+
+
+
+static union node *
+copynode(union node *n, struct nodecopystate *state)
+{
+	union node *new;
+
+	%COPY
+	return new;
+}
+
+
+static struct nodelist *
+copynodelist(struct nodelist *lp, struct nodecopystate *state)
+{
+	struct nodelist *start;
+	struct nodelist **lpp;
+
+	lpp = &start;
+	while (lp) {
+		*lpp = state->block;
+		state->block = (char *)state->block +
+		    ALIGN(sizeof(struct nodelist));
+		(*lpp)->n = copynode(lp->n, state);
+		lp = lp->next;
+		lpp = &(*lpp)->next;
+	}
+	*lpp = NULL;
+	return start;
+}
+
+
+
+static char *
+nodesavestr(const char *s, struct nodecopystate *state)
+{
+	const char *p = s;
+	char *q = state->string;
+	char   *rtn = state->string;
+
+	while ((*q++ = *p++) != '\0')
+		continue;
+	state->string = q;
+	return rtn;
+}
+
+
+void
+reffunc(struct funcdef *fn)
+{
+	if (fn)
+		fn->refcount++;
+}
+
+
+/*
+ * Decrement the reference count of a function definition, freeing it
+ * if it falls to 0.
+ */
+
+void
+unreffunc(struct funcdef *fn)
+{
+	if (fn) {
+		fn->refcount--;
+		if (fn->refcount > 0)
+			return;
+		ckfree(fn);
+	}
+}
diff --git a/bin/1sh/nodetypes b/bin/1sh/nodetypes
new file mode 100644
index 00000000..51facbe8
--- /dev/null
+++ b/bin/1sh/nodetypes
@@ -0,0 +1,145 @@
+#-
+# Copyright (c) 1991, 1993
+#	The Regents of the University of California.  All rights reserved.
+#
+# This code is derived from software contributed to Berkeley by
+# Kenneth Almquist.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. Neither the name of the University nor the names of its contributors
+#    may be used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+#	@(#)nodetypes	8.2 (Berkeley) 5/4/95
+# $FreeBSD: releng/12.1/bin/sh/nodetypes 314436 2017-02-28 23:42:47Z imp $
+
+# This file describes the nodes used in parse trees.  Unindented lines
+# contain a node type followed by a structure tag.  Subsequent indented
+# lines specify the fields of the structure.  Several node types can share
+# the same structure, in which case the fields of the structure should be
+# specified only once.
+#
+# A field of a structure is described by the name of the field followed
+# by a type.  The currently implemented types are:
+#	nodeptr - a pointer to a node
+#	nodelist - a pointer to a list of nodes
+#	string - a pointer to a nul terminated string
+#	int - an integer
+#	other - any type that can be copied by assignment
+#	temp - a field that doesn't have to be copied when the node is copied
+# The last two types should be followed by the text of a C declaration for
+# the field.
+
+NSEMI nbinary			# two commands separated by a semicolon
+	type	  int
+	ch1	  nodeptr		# the first child
+	ch2	  nodeptr		# the second child
+
+NCMD ncmd			# a simple command
+	type	  int
+	args	  nodeptr		# the arguments
+	redirect  nodeptr		# list of file redirections
+
+NPIPE npipe			# a pipeline
+	type	  int
+	backgnd	  int			# set to run pipeline in background
+	cmdlist	  nodelist		# the commands in the pipeline
+
+NREDIR nredir			# redirection (of a compex command)
+	type	  int
+	n	  nodeptr		# the command
+	redirect  nodeptr		# list of file redirections
+
+NBACKGND nredir			# run command in background
+NSUBSHELL nredir		# run command in a subshell
+
+NAND nbinary			# the && operator
+NOR nbinary			# the || operator
+
+NIF nif				# the if statement.  Elif clauses are handled
+	type	  int		    # using multiple if nodes.
+	test	  nodeptr		# if test
+	ifpart	  nodeptr		# then ifpart
+	elsepart  nodeptr		# else elsepart
+
+NWHILE nbinary			# the while statement.  First child is the test
+NUNTIL nbinary			# the until statement
+
+NFOR nfor			# the for statement
+	type	  int
+	args	  nodeptr		# for var in args
+	body	  nodeptr		# do body; done
+	var	  string		# the for variable
+
+NCASE ncase			# a case statement
+	type	  int
+	expr	  nodeptr		# the word to switch on
+	cases	  nodeptr		# the list of cases (NCLIST nodes)
+
+NCLIST nclist			# a case ending with ;;
+	type	  int
+	next	  nodeptr		# the next case in list
+	pattern	  nodeptr		# list of patterns for this case
+	body	  nodeptr		# code to execute for this case
+
+NCLISTFALLTHRU nclist		# a case ending with ;&
+
+NDEFUN narg			# define a function.  The "next" field contains
+				# the body of the function.
+
+NARG narg			# represents a word
+	type	  int
+	next	  nodeptr		# next word in list
+	text	  string		# the text of the word
+	backquote nodelist		# list of commands in back quotes
+
+NTO nfile			# fd> fname
+NFROM nfile			# fd< fname
+NFROMTO nfile			# fd<> fname
+NAPPEND nfile			# fd>> fname
+NCLOBBER nfile			# fd>| fname
+	type	  int
+	fd	  int			# file descriptor being redirected
+	next	  nodeptr		# next redirection in list
+	fname	  nodeptr		# file name, in a NARG node
+	expfname  temp	char *expfname	# actual file name
+
+NTOFD ndup			# fd<&dupfd
+NFROMFD ndup			# fd>&dupfd
+	type	  int
+	fd	  int			# file descriptor being redirected
+	next	  nodeptr		# next redirection in list
+	dupfd	  int			# file descriptor to duplicate
+	vname	  nodeptr		# file name if fd>&$var
+
+
+NHERE nhere			# fd<<\!
+NXHERE nhere			# fd<<!
+	type	  int
+	fd	  int			# file descriptor being redirected
+	next	  nodeptr		# next redirection in list
+	doc	  nodeptr		# input to command (NARG node)
+	expdoc    temp	const char *expdoc	# actual document (for NXHERE)
+
+NNOT nnot			# ! command  (actually pipeline)
+	type	int
+	com	nodeptr
diff --git a/bin/1sh/options.c b/bin/1sh/options.c
new file mode 100644
index 00000000..a1bb57ca
--- /dev/null
+++ b/bin/1sh/options.c
@@ -0,0 +1,594 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)options.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/options.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#define DEFINE_OPTIONS
+#include "options.h"
+#undef DEFINE_OPTIONS
+#include "nodes.h"	/* for other header files */
+#include "eval.h"
+#include "jobs.h"
+#include "input.h"
+#include "output.h"
+#include "trap.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "builtins.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+char *arg0;			/* value of $0 */
+struct shparam shellparam;	/* current positional parameters */
+char **argptr;			/* argument list for builtin commands */
+char *shoptarg;			/* set by nextopt (like getopt) */
+char *nextopt_optptr;		/* used by nextopt */
+
+char *minusc;			/* argument to -c option */
+
+
+static void options(int);
+static void minus_o(char *, int);
+static void setoption(int, int);
+static void setoptionbyindex(int, int);
+static void setparam(int, char **);
+static int getopts(char *, char *, char **, char ***, char **);
+
+
+/*
+ * Process the shell command line arguments.
+ */
+
+void
+procargs(int argc, char **argv)
+{
+	int i;
+	char *scriptname;
+
+	argptr = argv;
+	if (argc > 0)
+		argptr++;
+	for (i = 0; i < NOPTS; i++)
+		optval[i] = 2;
+	privileged = (getuid() != geteuid() || getgid() != getegid());
+	options(1);
+	if (*argptr == NULL && minusc == NULL)
+		sflag = 1;
+	if (iflag != 0 && sflag == 1 && isatty(0) && isatty(1)) {
+		iflag = 1;
+		if (Eflag == 2)
+			Eflag = 1;
+	}
+	if (mflag == 2)
+		mflag = iflag;
+	for (i = 0; i < NOPTS; i++)
+		if (optval[i] == 2)
+			optval[i] = 0;
+	arg0 = argv[0];
+	if (sflag == 0 && minusc == NULL) {
+		scriptname = *argptr++;
+		setinputfile(scriptname, 0);
+		commandname = arg0 = scriptname;
+	}
+	/* POSIX 1003.2: first arg after -c cmd is $0, remainder $1... */
+	if (argptr && minusc && *argptr)
+		arg0 = *argptr++;
+
+	shellparam.p = argptr;
+	shellparam.reset = 1;
+	/* assert(shellparam.malloc == 0 && shellparam.nparam == 0); */
+	while (*argptr) {
+		shellparam.nparam++;
+		argptr++;
+	}
+	optschanged();
+}
+
+
+void
+optschanged(void)
+{
+	setinteractive();
+#ifndef NO_HISTORY
+	histedit();
+#endif
+	setjobctl(mflag);
+}
+
+/*
+ * Process shell options.  The global variable argptr contains a pointer
+ * to the argument list; we advance it past the options.
+ * If cmdline is true, process the shell's argv; otherwise, process arguments
+ * to the set special builtin.
+ */
+
+static void
+options(int cmdline)
+{
+	char *kp, *p;
+	int val;
+	int c;
+
+	if (cmdline)
+		minusc = NULL;
+	while ((p = *argptr) != NULL) {
+		argptr++;
+		if ((c = *p++) == '-') {
+			val = 1;
+			/* A "-" or  "--" terminates options */
+			if (p[0] == '\0')
+				goto end_options1;
+			if (p[0] == '-' && p[1] == '\0')
+				goto end_options2;
+			/**
+			 * For the benefit of `#!' lines in shell scripts,
+			 * treat a string of '-- *#.*' the same as '--'.
+			 * This is needed so that a script starting with:
+			 *	#!/bin/sh -- # -*- perl -*-
+			 * will continue to work after a change is made to
+			 * kern/imgact_shell.c to NOT token-ize the options
+			 * specified on a '#!' line.  A bit of a kludge,
+			 * but that trick is recommended in documentation
+			 * for some scripting languages, and we might as
+			 * well continue to support it.
+			 */
+			if (p[0] == '-') {
+				kp = p + 1;
+				while (*kp == ' ' || *kp == '\t')
+					kp++;
+				if (*kp == '#' || *kp == '\0')
+					goto end_options2;
+			}
+		} else if (c == '+') {
+			val = 0;
+		} else {
+			argptr--;
+			break;
+		}
+		while ((c = *p++) != '\0') {
+			if (c == 'c' && cmdline) {
+				char *q;
+
+				q = *argptr++;
+				if (q == NULL || minusc != NULL)
+					error("Bad -c option");
+				minusc = q;
+			} else if (c == 'o') {
+				minus_o(*argptr, val);
+				if (*argptr)
+					argptr++;
+			} else
+				setoption(c, val);
+		}
+	}
+	return;
+
+	/* When processing `set', a single "-" means turn off -x and -v */
+end_options1:
+	if (!cmdline) {
+		xflag = vflag = 0;
+		return;
+	}
+
+	/*
+	 * When processing `set', a "--" means the remaining arguments
+	 * replace the positional parameters in the active shell.  If
+	 * there are no remaining options, then all the positional
+	 * parameters are cleared (equivalent to doing ``shift $#'').
+	 */
+end_options2:
+	if (!cmdline) {
+		if (*argptr == NULL)
+			setparam(0, argptr);
+		return;
+	}
+
+	/*
+	 * At this point we are processing options given to 'sh' on a command
+	 * line.  If an end-of-options marker ("-" or "--") is followed by an
+	 * arg of "#", then skip over all remaining arguments.  Some scripting
+	 * languages (e.g.: perl) document that /bin/sh will implement this
+	 * behavior, and they recommend that users take advantage of it to
+	 * solve certain issues that can come up when writing a perl script.
+	 * Yes, this feature is in /bin/sh to help users write perl scripts.
+	 */
+	p = *argptr;
+	if (p != NULL && p[0] == '#' && p[1] == '\0') {
+		while (*argptr != NULL)
+			argptr++;
+		/* We need to keep the final argument */
+		argptr--;
+	}
+}
+
+static void
+minus_o(char *name, int val)
+{
+	int i;
+	const unsigned char *on;
+	size_t len;
+
+	if (name == NULL) {
+		if (val) {
+			/* "Pretty" output. */
+			out1str("Current option settings\n");
+			for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
+				out1fmt("%-16.*s%s\n", *on, on + 1,
+					optval[i] ? "on" : "off");
+		} else {
+			/* Output suitable for re-input to shell. */
+			for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
+				out1fmt("%s %co %.*s%s",
+				    i % 6 == 0 ? "set" : "",
+				    optval[i] ? '-' : '+',
+				    *on, on + 1,
+				    i % 6 == 5 || i == NOPTS - 1 ? "\n" : "");
+		}
+	} else {
+		len = strlen(name);
+		for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
+			if (*on == len && memcmp(on + 1, name, len) == 0) {
+				setoptionbyindex(i, val);
+				return;
+			}
+		error("Illegal option -o %s", name);
+	}
+}
+
+
+static void
+setoptionbyindex(int idx, int val)
+{
+	if (&optval[idx] == &privileged && !val && privileged) {
+		if (setgid(getgid()) == -1)
+			error("setgid");
+		if (setuid(getuid()) == -1)
+			error("setuid");
+	}
+	optval[idx] = val;
+	if (val) {
+		/* #%$ hack for ksh semantics */
+		if (&optval[idx] == &Vflag)
+			Eflag = 0;
+		else if (&optval[idx] == &Eflag)
+			Vflag = 0;
+	}
+}
+
+static void
+setoption(int flag, int val)
+{
+	int i;
+
+	for (i = 0; i < NSHORTOPTS; i++)
+		if (optletter[i] == flag) {
+			setoptionbyindex(i, val);
+			return;
+		}
+	error("Illegal option -%c", flag);
+}
+
+
+/*
+ * Set the shell parameters.
+ */
+
+static void
+setparam(int argc, char **argv)
+{
+	char **newparam;
+	char **ap;
+
+	ap = newparam = ckmalloc((argc + 1) * sizeof *ap);
+	while (*argv) {
+		*ap++ = savestr(*argv++);
+	}
+	*ap = NULL;
+	freeparam(&shellparam);
+	shellparam.malloc = 1;
+	shellparam.nparam = argc;
+	shellparam.p = newparam;
+	shellparam.optp = NULL;
+	shellparam.reset = 1;
+	shellparam.optnext = NULL;
+}
+
+
+/*
+ * Free the list of positional parameters.
+ */
+
+void
+freeparam(struct shparam *param)
+{
+	char **ap;
+
+	if (param->malloc) {
+		for (ap = param->p ; *ap ; ap++)
+			ckfree(*ap);
+		ckfree(param->p);
+	}
+	if (param->optp) {
+		for (ap = param->optp ; *ap ; ap++)
+			ckfree(*ap);
+		ckfree(param->optp);
+	}
+}
+
+
+
+/*
+ * The shift builtin command.
+ */
+
+int
+shiftcmd(int argc, char **argv)
+{
+	int i, n;
+
+	n = 1;
+	if (argc > 1)
+		n = number(argv[1]);
+	if (n > shellparam.nparam)
+		return 1;
+	INTOFF;
+	shellparam.nparam -= n;
+	if (shellparam.malloc)
+		for (i = 0; i < n; i++)
+			ckfree(shellparam.p[i]);
+	memmove(shellparam.p, shellparam.p + n,
+	    (shellparam.nparam + 1) * sizeof(shellparam.p[0]));
+	shellparam.reset = 1;
+	INTON;
+	return 0;
+}
+
+
+
+/*
+ * The set builtin command.
+ */
+
+int
+setcmd(int argc, char **argv)
+{
+	if (argc == 1)
+		return showvarscmd(argc, argv);
+	INTOFF;
+	options(0);
+	optschanged();
+	if (*argptr != NULL) {
+		setparam(argc - (argptr - argv), argptr);
+	}
+	INTON;
+	return 0;
+}
+
+
+void
+getoptsreset(const char *value)
+{
+	while (*value == '0')
+		value++;
+	if (strcmp(value, "1") == 0)
+		shellparam.reset = 1;
+}
+
+/*
+ * The getopts builtin.  Shellparam.optnext points to the next argument
+ * to be processed.  Shellparam.optptr points to the next character to
+ * be processed in the current argument.  If shellparam.optnext is NULL,
+ * then it's the first time getopts has been called.
+ */
+
+int
+getoptscmd(int argc, char **argv)
+{
+	char **optbase = NULL, **ap;
+	int i;
+
+	if (argc < 3)
+		error("usage: getopts optstring var [arg]");
+
+	if (shellparam.reset == 1) {
+		INTOFF;
+		if (shellparam.optp) {
+			for (ap = shellparam.optp ; *ap ; ap++)
+				ckfree(*ap);
+			ckfree(shellparam.optp);
+			shellparam.optp = NULL;
+		}
+		if (argc > 3) {
+			shellparam.optp = ckmalloc((argc - 2) * sizeof *ap);
+			memset(shellparam.optp, '\0', (argc - 2) * sizeof *ap);
+			for (i = 0; i < argc - 3; i++)
+				shellparam.optp[i] = savestr(argv[i + 3]);
+		}
+		INTON;
+		optbase = argc == 3 ? shellparam.p : shellparam.optp;
+		shellparam.optnext = optbase;
+		shellparam.optptr = NULL;
+		shellparam.reset = 0;
+	} else
+		optbase = shellparam.optp ? shellparam.optp : shellparam.p;
+
+	return getopts(argv[1], argv[2], optbase, &shellparam.optnext,
+		       &shellparam.optptr);
+}
+
+static int
+getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
+    char **optptr)
+{
+	char *p, *q;
+	char c = '?';
+	int done = 0;
+	int ind = 0;
+	int err = 0;
+	char s[10];
+	const char *newoptarg = NULL;
+
+	if ((p = *optptr) == NULL || *p == '\0') {
+		/* Current word is done, advance */
+		if (*optnext == NULL)
+			return 1;
+		p = **optnext;
+		if (p == NULL || *p != '-' || *++p == '\0') {
+atend:
+			ind = *optnext - optfirst + 1;
+			*optnext = NULL;
+			p = NULL;
+			done = 1;
+			goto out;
+		}
+		(*optnext)++;
+		if (p[0] == '-' && p[1] == '\0')	/* check for "--" */
+			goto atend;
+	}
+
+	c = *p++;
+	for (q = optstr; *q != c; ) {
+		if (*q == '\0') {
+			if (optstr[0] == ':') {
+				s[0] = c;
+				s[1] = '\0';
+				newoptarg = s;
+			}
+			else
+				out2fmt_flush("Illegal option -%c\n", c);
+			c = '?';
+			goto out;
+		}
+		if (*++q == ':')
+			q++;
+	}
+
+	if (*++q == ':') {
+		if (*p == '\0' && (p = **optnext) == NULL) {
+			if (optstr[0] == ':') {
+				s[0] = c;
+				s[1] = '\0';
+				newoptarg = s;
+				c = ':';
+			}
+			else {
+				out2fmt_flush("No arg for -%c option\n", c);
+				c = '?';
+			}
+			goto out;
+		}
+
+		if (p == **optnext)
+			(*optnext)++;
+		newoptarg = p;
+		p = NULL;
+	}
+
+out:
+	if (*optnext != NULL)
+		ind = *optnext - optfirst + 1;
+	*optptr = p;
+	if (newoptarg != NULL)
+		err |= setvarsafe("OPTARG", newoptarg, 0);
+	else {
+		INTOFF;
+		err |= unsetvar("OPTARG");
+		INTON;
+	}
+	fmtstr(s, sizeof(s), "%d", ind);
+	err |= setvarsafe("OPTIND", s, VNOFUNC);
+	s[0] = c;
+	s[1] = '\0';
+	err |= setvarsafe(optvar, s, 0);
+	if (err) {
+		*optnext = NULL;
+		*optptr = NULL;
+		flushall();
+		exraise(EXERROR);
+	}
+	return done;
+}
+
+/*
+ * Standard option processing (a la getopt) for builtin routines.  The
+ * only argument that is passed to nextopt is the option string; the
+ * other arguments are unnecessary.  It returns the option, or '\0' on
+ * end of input.
+ */
+
+int
+nextopt(const char *optstring)
+{
+	char *p;
+	const char *q;
+	char c;
+
+	if ((p = nextopt_optptr) == NULL || *p == '\0') {
+		p = *argptr;
+		if (p == NULL || *p != '-' || *++p == '\0')
+			return '\0';
+		argptr++;
+		if (p[0] == '-' && p[1] == '\0')	/* check for "--" */
+			return '\0';
+	}
+	c = *p++;
+	for (q = optstring ; *q != c ; ) {
+		if (*q == '\0')
+			error("Illegal option -%c", c);
+		if (*++q == ':')
+			q++;
+	}
+	if (*++q == ':') {
+		if (*p == '\0' && (p = *argptr++) == NULL)
+			error("No arg for -%c option", c);
+		shoptarg = p;
+		p = NULL;
+	}
+	nextopt_optptr = p;
+	return c;
+}
diff --git a/bin/1sh/options.h b/bin/1sh/options.h
new file mode 100644
index 00000000..007ea312
--- /dev/null
+++ b/bin/1sh/options.h
@@ -0,0 +1,117 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)options.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/options.h 345487 2019-03-24 22:10:26Z jilles $
+ */
+
+struct shparam {
+	int nparam;		/* # of positional parameters (without $0) */
+	unsigned char malloc;	/* if parameter list dynamically allocated */
+	unsigned char reset;	/* if getopts has been reset */
+	char **p;		/* parameter list */
+	char **optp;		/* parameter list for getopts */
+	char **optnext;		/* next parameter to be processed by getopts */
+	char *optptr;		/* used by getopts */
+};
+
+
+
+#define eflag optval[0]
+#define fflag optval[1]
+#define Iflag optval[2]
+#define iflag optval[3]
+#define mflag optval[4]
+#define nflag optval[5]
+#define sflag optval[6]
+#define xflag optval[7]
+#define vflag optval[8]
+#define Vflag optval[9]
+#define	Eflag optval[10]
+#define	Cflag optval[11]
+#define	aflag optval[12]
+#define	bflag optval[13]
+#define	uflag optval[14]
+#define	privileged optval[15]
+#define	Tflag optval[16]
+#define	Pflag optval[17]
+#define	hflag optval[18]
+#define	nologflag optval[19]
+#define	pipefailflag optval[20]
+
+#define NSHORTOPTS	19
+#define NOPTS		21
+
+extern char optval[NOPTS];
+extern const char optletter[NSHORTOPTS];
+#ifdef DEFINE_OPTIONS
+char optval[NOPTS];
+const char optletter[NSHORTOPTS] = "efIimnsxvVECabupTPh";
+static const unsigned char optname[] =
+	"\007errexit"
+	"\006noglob"
+	"\011ignoreeof"
+	"\013interactive"
+	"\007monitor"
+	"\006noexec"
+	"\005stdin"
+	"\006xtrace"
+	"\007verbose"
+	"\002vi"
+	"\005emacs"
+	"\011noclobber"
+	"\011allexport"
+	"\006notify"
+	"\007nounset"
+	"\012privileged"
+	"\012trapsasync"
+	"\010physical"
+	"\010trackall"
+	"\005nolog"
+	"\010pipefail"
+;
+#endif
+
+
+extern char *minusc;		/* argument to -c option */
+extern char *arg0;		/* $0 */
+extern struct shparam shellparam;  /* $@ */
+extern char **argptr;		/* argument list for builtin commands */
+extern char *shoptarg;		/* set by nextopt */
+extern char *nextopt_optptr;	/* used by nextopt */
+
+void procargs(int, char **);
+void optschanged(void);
+void freeparam(struct shparam *);
+int nextopt(const char *);
+void getoptsreset(const char *);
diff --git a/bin/1sh/output.c b/bin/1sh/output.c
new file mode 100644
index 00000000..af93ec6d
--- /dev/null
+++ b/bin/1sh/output.c
@@ -0,0 +1,376 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)output.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/output.c 345613 2019-03-27 21:53:44Z jilles $ */
+
+/*
+ * Shell output routines.  We use our own output routines because:
+ *	When a builtin command is interrupted we have to discard
+ *		any pending output.
+ *	When a builtin command appears in back quotes, we want to
+ *		save the output of the command in a region obtained
+ *		via malloc, rather than doing a fork and reading the
+ *		output of the command via a pipe.
+ */
+
+#include <stdio.h>	/* defines BUFSIZ */
+#include <string.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "shell.h"
+#include "syntax.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "var.h"
+
+
+#define OUTBUFSIZ BUFSIZ
+#define MEM_OUT -2		/* output to dynamically allocated memory */
+#define OUTPUT_ERR 01		/* error occurred on output */
+
+static int doformat_wr(void *, const char *, int);
+
+struct output output = {NULL, NULL, NULL, OUTBUFSIZ, 1, 0};
+struct output errout = {NULL, NULL, NULL, 256, 2, 0};
+struct output memout = {NULL, NULL, NULL, 64, MEM_OUT, 0};
+struct output *out1 = &output;
+struct output *out2 = &errout;
+
+void
+outcslow(int c, struct output *file)
+{
+	outc(c, file);
+}
+
+void
+out1str(const char *p)
+{
+	outstr(p, out1);
+}
+
+void
+out1qstr(const char *p)
+{
+	outqstr(p, out1);
+}
+
+void
+out2str(const char *p)
+{
+	outstr(p, out2);
+}
+
+void
+out2qstr(const char *p)
+{
+	outqstr(p, out2);
+}
+
+void
+outstr(const char *p, struct output *file)
+{
+	outbin(p, strlen(p), file);
+}
+
+static void
+byteseq(int ch, struct output *file)
+{
+	char seq[4];
+
+	seq[0] = '\\';
+	seq[1] = (ch >> 6 & 0x3) + '0';
+	seq[2] = (ch >> 3 & 0x7) + '0';
+	seq[3] = (ch & 0x7) + '0';
+	outbin(seq, 4, file);
+}
+
+static void
+outdqstr(const char *p, struct output *file)
+{
+	const char *end;
+	mbstate_t mbs;
+	size_t clen;
+	wchar_t wc;
+
+	memset(&mbs, '\0', sizeof(mbs));
+	end = p + strlen(p);
+	outstr("$'", file);
+	while ((clen = mbrtowc(&wc, p, end - p + 1, &mbs)) != 0) {
+		if (clen == (size_t)-2) {
+			while (p < end)
+				byteseq(*p++, file);
+			break;
+		}
+		if (clen == (size_t)-1) {
+			memset(&mbs, '\0', sizeof(mbs));
+			byteseq(*p++, file);
+			continue;
+		}
+		if (wc == L'\n')
+			outcslow('\n', file), p++;
+		else if (wc == L'\r')
+			outstr("\\r", file), p++;
+		else if (wc == L'\t')
+			outstr("\\t", file), p++;
+		else if (!iswprint(wc)) {
+			for (; clen > 0; clen--)
+				byteseq(*p++, file);
+		} else {
+			if (wc == L'\'' || wc == L'\\')
+				outcslow('\\', file);
+			outbin(p, clen, file);
+			p += clen;
+		}
+	}
+	outcslow('\'', file);
+}
+
+/* Like outstr(), but quote for re-input into the shell. */
+void
+outqstr(const char *p, struct output *file)
+{
+	int i;
+
+	if (p[0] == '\0') {
+		outstr("''", file);
+		return;
+	}
+	for (i = 0; p[i] != '\0'; i++) {
+		if ((p[i] > '\0' && p[i] < ' ' && p[i] != '\n') ||
+		    (p[i] & 0x80) != 0 || p[i] == '\'') {
+			outdqstr(p, file);
+			return;
+		}
+	}
+
+	if (p[strcspn(p, "|&;<>()$`\\\" \n*?[~#=")] == '\0' ||
+			strcmp(p, "[") == 0) {
+		outstr(p, file);
+		return;
+	}
+
+	outcslow('\'', file);
+	outstr(p, file);
+	outcslow('\'', file);
+}
+
+void
+outbin(const void *data, size_t len, struct output *file)
+{
+	const char *p;
+
+	p = data;
+	while (len-- > 0)
+		outc(*p++, file);
+}
+
+void
+emptyoutbuf(struct output *dest)
+{
+	int offset, newsize;
+
+	if (dest->buf == NULL) {
+		INTOFF;
+		dest->buf = ckmalloc(dest->bufsize);
+		dest->nextc = dest->buf;
+		dest->bufend = dest->buf + dest->bufsize;
+		INTON;
+	} else if (dest->fd == MEM_OUT) {
+		offset = dest->nextc - dest->buf;
+		newsize = dest->bufsize << 1;
+		INTOFF;
+		dest->buf = ckrealloc(dest->buf, newsize);
+		dest->bufsize = newsize;
+		dest->bufend = dest->buf + newsize;
+		dest->nextc = dest->buf + offset;
+		INTON;
+	} else {
+		flushout(dest);
+	}
+}
+
+
+void
+flushall(void)
+{
+	flushout(&output);
+	flushout(&errout);
+}
+
+
+void
+flushout(struct output *dest)
+{
+
+	if (dest->buf == NULL || dest->nextc == dest->buf || dest->fd < 0)
+		return;
+	if (xwrite(dest->fd, dest->buf, dest->nextc - dest->buf) < 0)
+		dest->flags |= OUTPUT_ERR;
+	dest->nextc = dest->buf;
+}
+
+
+void
+freestdout(void)
+{
+	output.nextc = output.buf;
+}
+
+
+int
+outiserror(struct output *file)
+{
+	return (file->flags & OUTPUT_ERR);
+}
+
+
+void
+outclearerror(struct output *file)
+{
+	file->flags &= ~OUTPUT_ERR;
+}
+
+
+void
+outfmt(struct output *file, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	doformat(file, fmt, ap);
+	va_end(ap);
+}
+
+
+void
+out1fmt(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	doformat(out1, fmt, ap);
+	va_end(ap);
+}
+
+void
+out2fmt_flush(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	doformat(out2, fmt, ap);
+	va_end(ap);
+	flushout(out2);
+}
+
+void
+fmtstr(char *outbuf, int length, const char *fmt, ...)
+{
+	va_list ap;
+
+	INTOFF;
+	va_start(ap, fmt);
+	vsnprintf(outbuf, length, fmt, ap);
+	va_end(ap);
+	INTON;
+}
+
+static int
+doformat_wr(void *cookie, const char *buf, int len)
+{
+	struct output *o;
+
+	o = (struct output *)cookie;
+	outbin(buf, len, o);
+
+	return (len);
+}
+
+void
+doformat(struct output *dest, const char *f, va_list ap)
+{
+	FILE *fp;
+
+	if ((fp = fwopen(dest, doformat_wr)) != NULL) {
+		vfprintf(fp, f, ap);
+		fclose(fp);
+	}
+}
+
+FILE *
+out1fp(void)
+{
+	return fwopen(out1, doformat_wr);
+}
+
+/*
+ * Version of write which resumes after a signal is caught.
+ */
+
+int
+xwrite(int fd, const char *buf, int nbytes)
+{
+	int ntry;
+	int i;
+	int n;
+
+	n = nbytes;
+	ntry = 0;
+	for (;;) {
+		i = write(fd, buf, n);
+		if (i > 0) {
+			if ((n -= i) <= 0)
+				return nbytes;
+			buf += i;
+			ntry = 0;
+		} else if (i == 0) {
+			if (++ntry > 10)
+				return nbytes - n;
+		} else if (errno != EINTR) {
+			return -1;
+		}
+	}
+}
diff --git a/bin/1sh/output.h b/bin/1sh/output.h
new file mode 100644
index 00000000..8d5ded6f
--- /dev/null
+++ b/bin/1sh/output.h
@@ -0,0 +1,87 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)output.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/output.h 345613 2019-03-27 21:53:44Z jilles $
+ */
+
+#ifndef OUTPUT_INCL
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+
+struct output {
+	char *nextc;
+	char *bufend;
+	char *buf;
+	int bufsize;
+	short fd;
+	short flags;
+};
+
+extern struct output output; /* to fd 1 */
+extern struct output errout; /* to fd 2 */
+extern struct output memout;
+extern struct output *out1; /* &memout if backquote, otherwise &output */
+extern struct output *out2; /* &memout if backquote with 2>&1, otherwise
+			       &errout */
+
+void outcslow(int, struct output *);
+void out1str(const char *);
+void out1qstr(const char *);
+void out2str(const char *);
+void out2qstr(const char *);
+void outstr(const char *, struct output *);
+void outqstr(const char *, struct output *);
+void outbin(const void *, size_t, struct output *);
+void emptyoutbuf(struct output *);
+void flushall(void);
+void flushout(struct output *);
+void freestdout(void);
+int outiserror(struct output *);
+void outclearerror(struct output *);
+void outfmt(struct output *, const char *, ...) __attribute__((format(printf, 2, 3)));
+void out1fmt(const char *, ...) __attribute__((format(printf, 1, 2)));
+void out2fmt_flush(const char *, ...) __attribute__((format(printf, 1, 2)));
+void fmtstr(char *, int, const char *, ...) __attribute__((format(printf, 3, 4)));
+void doformat(struct output *, const char *, va_list) __attribute__((format(printf, 2, 0)));
+FILE *out1fp(void);
+int xwrite(int, const char *, int);
+
+#define outc(c, file)	((file)->nextc == (file)->bufend ? (emptyoutbuf(file), *(file)->nextc++ = (c)) : (*(file)->nextc++ = (c)))
+#define out1c(c)	outc(c, out1);
+#define out2c(c)	outcslow(c, out2);
+
+#define OUTPUT_INCL
+#endif
diff --git a/bin/1sh/parser.c b/bin/1sh/parser.c
new file mode 100644
index 00000000..b2f761c8
--- /dev/null
+++ b/bin/1sh/parser.c
@@ -0,0 +1,2182 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/parser.c 334008 2018-05-21 21:52:48Z jilles $ */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+#include "shell.h"
+#include "parser.h"
+#include "nodes.h"
+#include "expand.h"	/* defines rmescapes() */
+#include "syntax.h"
+#include "options.h"
+#include "input.h"
+#include "output.h"
+#include "var.h"
+#include "error.h"
+#include "memalloc.h"
+#include "mystring.h"
+#include "alias.h"
+#include "show.h"
+#include "eval.h"
+#include "exec.h"	/* to check for special builtins */
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+/*
+ * Shell command parser.
+ */
+
+#define	PROMPTLEN	128
+
+/* values of checkkwd variable */
+#define CHKALIAS	0x1
+#define CHKKWD		0x2
+#define CHKNL		0x4
+
+/* values returned by readtoken */
+#include "token.h"
+
+
+
+struct heredoc {
+	struct heredoc *next;	/* next here document in list */
+	union node *here;		/* redirection node */
+	char *eofmark;		/* string indicating end of input */
+	int striptabs;		/* if set, strip leading tabs */
+};
+
+struct parser_temp {
+	struct parser_temp *next;
+	void *data;
+};
+
+
+static struct heredoc *heredoclist;	/* list of here documents to read */
+static int doprompt;		/* if set, prompt the user */
+static int needprompt;		/* true if interactive and at start of line */
+static int lasttoken;		/* last token read */
+static int tokpushback;		/* last token pushed back */
+static char *wordtext;		/* text of last word returned by readtoken */
+static int checkkwd;
+static struct nodelist *backquotelist;
+static union node *redirnode;
+static struct heredoc *heredoc;
+static int quoteflag;		/* set if (part of) last token was quoted */
+static int startlinno;		/* line # where last token started */
+static int funclinno;		/* line # where the current function started */
+static struct parser_temp *parser_temp;
+
+#define NOEOFMARK ((const char *)&heredoclist)
+
+
+static union node *list(int);
+static union node *andor(void);
+static union node *pipeline(void);
+static union node *command(void);
+static union node *simplecmd(union node **, union node *);
+static union node *makename(void);
+static union node *makebinary(int type, union node *n1, union node *n2);
+static void parsefname(void);
+static void parseheredoc(void);
+static int peektoken(void);
+static int readtoken(void);
+static int xxreadtoken(void);
+static int readtoken1(int, const char *, const char *, int);
+static int noexpand(char *);
+static void consumetoken(int);
+static void synexpect(int) __attribute__((noreturn));
+static void synerror(const char *) __attribute__((noreturn));
+static void setprompt(int);
+static char *expandprompt(const char *);
+static int pgetc_linecont(void);
+
+
+static void *
+parser_temp_alloc(size_t len)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	t = ckmalloc(sizeof(*t));
+	t->data = NULL;
+	t->next = parser_temp;
+	parser_temp = t;
+	t->data = ckmalloc(len);
+	INTON;
+	return t->data;
+}
+
+
+static void *
+parser_temp_realloc(void *ptr, size_t len)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	t = parser_temp;
+	if (ptr != t->data)
+		error("bug: parser_temp_realloc misused");
+	t->data = ckrealloc(t->data, len);
+	INTON;
+	return t->data;
+}
+
+
+static void
+parser_temp_free_upto(void *ptr)
+{
+	struct parser_temp *t;
+	int done = 0;
+
+	INTOFF;
+	while (parser_temp != NULL && !done) {
+		t = parser_temp;
+		parser_temp = t->next;
+		done = t->data == ptr;
+		ckfree(t->data);
+		ckfree(t);
+	}
+	INTON;
+	if (!done)
+		error("bug: parser_temp_free_upto misused");
+}
+
+
+static void
+parser_temp_free_all(void)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	while (parser_temp != NULL) {
+		t = parser_temp;
+		parser_temp = t->next;
+		ckfree(t->data);
+		ckfree(t);
+	}
+	INTON;
+}
+
+
+/*
+ * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
+ * valid parse tree indicating a blank line.)
+ */
+
+union node *
+parsecmd(int interact)
+{
+	int t;
+
+	/* This assumes the parser is not re-entered,
+	 * which could happen if we add command substitution on PS1/PS2.
+	 */
+	parser_temp_free_all();
+	heredoclist = NULL;
+
+	tokpushback = 0;
+	checkkwd = 0;
+	doprompt = interact;
+	if (doprompt)
+		setprompt(1);
+	else
+		setprompt(0);
+	needprompt = 0;
+	t = readtoken();
+	if (t == TEOF)
+		return NEOF;
+	if (t == TNL)
+		return NULL;
+	tokpushback++;
+	return list(1);
+}
+
+
+/*
+ * Read and parse words for wordexp.
+ * Returns a list of NARG nodes; NULL if there are no words.
+ */
+union node *
+parsewordexp(void)
+{
+	union node *n, *first = NULL, **pnext;
+	int t;
+
+	/* This assumes the parser is not re-entered,
+	 * which could happen if we add command substitution on PS1/PS2.
+	 */
+	parser_temp_free_all();
+	heredoclist = NULL;
+
+	tokpushback = 0;
+	checkkwd = 0;
+	doprompt = 0;
+	setprompt(0);
+	needprompt = 0;
+	pnext = &first;
+	while ((t = readtoken()) != TEOF) {
+		if (t != TWORD)
+			synexpect(TWORD);
+		n = makename();
+		*pnext = n;
+		pnext = &n->narg.next;
+	}
+	return first;
+}
+
+
+static union node *
+list(int nlflag)
+{
+	union node *ntop, *n1, *n2, *n3;
+	int tok;
+
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	if (!nlflag && tokendlist[peektoken()])
+		return NULL;
+	ntop = n1 = NULL;
+	for (;;) {
+		n2 = andor();
+		tok = readtoken();
+		if (tok == TBACKGND) {
+			if (n2 != NULL && n2->type == NPIPE) {
+				n2->npipe.backgnd = 1;
+			} else if (n2 != NULL && n2->type == NREDIR) {
+				n2->type = NBACKGND;
+			} else {
+				n3 = (union node *)stalloc(sizeof (struct nredir));
+				n3->type = NBACKGND;
+				n3->nredir.n = n2;
+				n3->nredir.redirect = NULL;
+				n2 = n3;
+			}
+		}
+		if (ntop == NULL)
+			ntop = n2;
+		else if (n1 == NULL) {
+			n1 = makebinary(NSEMI, ntop, n2);
+			ntop = n1;
+		}
+		else {
+			n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
+			n1->nbinary.ch2 = n3;
+			n1 = n3;
+		}
+		switch (tok) {
+		case TBACKGND:
+		case TSEMI:
+			tok = readtoken();
+			/* FALLTHROUGH */
+		case TNL:
+			if (tok == TNL) {
+				parseheredoc();
+				if (nlflag)
+					return ntop;
+			} else if (tok == TEOF && nlflag) {
+				parseheredoc();
+				return ntop;
+			} else {
+				tokpushback++;
+			}
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			if (!nlflag && tokendlist[peektoken()])
+				return ntop;
+			break;
+		case TEOF:
+			if (heredoclist)
+				parseheredoc();
+			else
+				pungetc();		/* push back EOF on input */
+			return ntop;
+		default:
+			if (nlflag)
+				synexpect(-1);
+			tokpushback++;
+			return ntop;
+		}
+	}
+}
+
+
+
+static union node *
+andor(void)
+{
+	union node *n;
+	int t;
+
+	n = pipeline();
+	for (;;) {
+		if ((t = readtoken()) == TAND) {
+			t = NAND;
+		} else if (t == TOR) {
+			t = NOR;
+		} else {
+			tokpushback++;
+			return n;
+		}
+		n = makebinary(t, n, pipeline());
+	}
+}
+
+
+
+static union node *
+pipeline(void)
+{
+	union node *n1, *n2, *pipenode;
+	struct nodelist *lp, *prev;
+	int negate, t;
+
+	negate = 0;
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	TRACE(("pipeline: entered\n"));
+	while (readtoken() == TNOT)
+		negate = !negate;
+	tokpushback++;
+	n1 = command();
+	if (readtoken() == TPIPE) {
+		pipenode = (union node *)stalloc(sizeof (struct npipe));
+		pipenode->type = NPIPE;
+		pipenode->npipe.backgnd = 0;
+		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+		pipenode->npipe.cmdlist = lp;
+		lp->n = n1;
+		do {
+			prev = lp;
+			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			t = readtoken();
+			tokpushback++;
+			if (t == TNOT)
+				lp->n = pipeline();
+			else
+				lp->n = command();
+			prev->next = lp;
+		} while (readtoken() == TPIPE);
+		lp->next = NULL;
+		n1 = pipenode;
+	}
+	tokpushback++;
+	if (negate) {
+		n2 = (union node *)stalloc(sizeof (struct nnot));
+		n2->type = NNOT;
+		n2->nnot.com = n1;
+		return n2;
+	} else
+		return n1;
+}
+
+
+
+static union node *
+command(void)
+{
+	union node *n1, *n2;
+	union node *ap, **app;
+	union node *cp, **cpp;
+	union node *redir, **rpp;
+	int t;
+	int is_subshell;
+
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	is_subshell = 0;
+	redir = NULL;
+	n1 = NULL;
+	rpp = &redir;
+
+	/* Check for redirection which may precede command */
+	while (readtoken() == TREDIR) {
+		*rpp = n2 = redirnode;
+		rpp = &n2->nfile.next;
+		parsefname();
+	}
+	tokpushback++;
+
+	switch (readtoken()) {
+	case TIF:
+		n1 = (union node *)stalloc(sizeof (struct nif));
+		n1->type = NIF;
+		if ((n1->nif.test = list(0)) == NULL)
+			synexpect(-1);
+		consumetoken(TTHEN);
+		n1->nif.ifpart = list(0);
+		n2 = n1;
+		while (readtoken() == TELIF) {
+			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
+			n2 = n2->nif.elsepart;
+			n2->type = NIF;
+			if ((n2->nif.test = list(0)) == NULL)
+				synexpect(-1);
+			consumetoken(TTHEN);
+			n2->nif.ifpart = list(0);
+		}
+		if (lasttoken == TELSE)
+			n2->nif.elsepart = list(0);
+		else {
+			n2->nif.elsepart = NULL;
+			tokpushback++;
+		}
+		consumetoken(TFI);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TWHILE:
+	case TUNTIL:
+		t = lasttoken;
+		if ((n1 = list(0)) == NULL)
+			synexpect(-1);
+		consumetoken(TDO);
+		n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
+		consumetoken(TDONE);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TFOR:
+		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
+			synerror("Bad for loop variable");
+		n1 = (union node *)stalloc(sizeof (struct nfor));
+		n1->type = NFOR;
+		n1->nfor.var = wordtext;
+		while (readtoken() == TNL)
+			;
+		if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
+			app = &ap;
+			while (readtoken() == TWORD) {
+				n2 = makename();
+				*app = n2;
+				app = &n2->narg.next;
+			}
+			*app = NULL;
+			n1->nfor.args = ap;
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				synexpect(-1);
+		} else {
+			static char argvars[5] = {
+				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
+			};
+			n2 = (union node *)stalloc(sizeof (struct narg));
+			n2->type = NARG;
+			n2->narg.text = argvars;
+			n2->narg.backquote = NULL;
+			n2->narg.next = NULL;
+			n1->nfor.args = n2;
+			/*
+			 * Newline or semicolon here is optional (but note
+			 * that the original Bourne shell only allowed NL).
+			 */
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				tokpushback++;
+		}
+		checkkwd = CHKNL | CHKKWD | CHKALIAS;
+		if ((t = readtoken()) == TDO)
+			t = TDONE;
+		else if (t == TBEGIN)
+			t = TEND;
+		else
+			synexpect(-1);
+		n1->nfor.body = list(0);
+		consumetoken(t);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TCASE:
+		n1 = (union node *)stalloc(sizeof (struct ncase));
+		n1->type = NCASE;
+		consumetoken(TWORD);
+		n1->ncase.expr = makename();
+		while (readtoken() == TNL);
+		if (lasttoken != TWORD || ! equal(wordtext, "in"))
+			synerror("expecting \"in\"");
+		cpp = &n1->ncase.cases;
+		checkkwd = CHKNL | CHKKWD, readtoken();
+		while (lasttoken != TESAC) {
+			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
+			cp->type = NCLIST;
+			app = &cp->nclist.pattern;
+			if (lasttoken == TLP)
+				readtoken();
+			for (;;) {
+				*app = ap = makename();
+				checkkwd = CHKNL | CHKKWD;
+				if (readtoken() != TPIPE)
+					break;
+				app = &ap->narg.next;
+				readtoken();
+			}
+			ap->narg.next = NULL;
+			if (lasttoken != TRP)
+				synexpect(TRP);
+			cp->nclist.body = list(0);
+
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			if ((t = readtoken()) != TESAC) {
+				if (t == TENDCASE)
+					;
+				else if (t == TFALLTHRU)
+					cp->type = NCLISTFALLTHRU;
+				else
+					synexpect(TENDCASE);
+				checkkwd = CHKNL | CHKKWD, readtoken();
+			}
+			cpp = &cp->nclist.next;
+		}
+		*cpp = NULL;
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TLP:
+		n1 = (union node *)stalloc(sizeof (struct nredir));
+		n1->type = NSUBSHELL;
+		n1->nredir.n = list(0);
+		n1->nredir.redirect = NULL;
+		consumetoken(TRP);
+		checkkwd = CHKKWD | CHKALIAS;
+		is_subshell = 1;
+		break;
+	case TBEGIN:
+		n1 = list(0);
+		consumetoken(TEND);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	/* A simple command must have at least one redirection or word. */
+	case TBACKGND:
+	case TSEMI:
+	case TAND:
+	case TOR:
+	case TPIPE:
+	case TENDCASE:
+	case TFALLTHRU:
+	case TEOF:
+	case TNL:
+	case TRP:
+		if (!redir)
+			synexpect(-1);
+	case TWORD:
+		tokpushback++;
+		n1 = simplecmd(rpp, redir);
+		return n1;
+	default:
+		synexpect(-1);
+	}
+
+	/* Now check for redirection which may follow command */
+	while (readtoken() == TREDIR) {
+		*rpp = n2 = redirnode;
+		rpp = &n2->nfile.next;
+		parsefname();
+	}
+	tokpushback++;
+	*rpp = NULL;
+	if (redir) {
+		if (!is_subshell) {
+			n2 = (union node *)stalloc(sizeof (struct nredir));
+			n2->type = NREDIR;
+			n2->nredir.n = n1;
+			n1 = n2;
+		}
+		n1->nredir.redirect = redir;
+	}
+
+	return n1;
+}
+
+
+static union node *
+simplecmd(union node **rpp, union node *redir)
+{
+	union node *args, **app;
+	union node **orig_rpp = rpp;
+	union node *n = NULL;
+	int special;
+	int savecheckkwd;
+
+	/* If we don't have any redirections already, then we must reset */
+	/* rpp to be the address of the local redir variable.  */
+	if (redir == NULL)
+		rpp = &redir;
+
+	args = NULL;
+	app = &args;
+	/*
+	 * We save the incoming value, because we need this for shell
+	 * functions.  There can not be a redirect or an argument between
+	 * the function name and the open parenthesis.
+	 */
+	orig_rpp = rpp;
+
+	savecheckkwd = CHKALIAS;
+
+	for (;;) {
+		checkkwd = savecheckkwd;
+		if (readtoken() == TWORD) {
+			n = makename();
+			*app = n;
+			app = &n->narg.next;
+			if (savecheckkwd != 0 && !isassignment(wordtext))
+				savecheckkwd = 0;
+		} else if (lasttoken == TREDIR) {
+			*rpp = n = redirnode;
+			rpp = &n->nfile.next;
+			parsefname();	/* read name of redirection file */
+		} else if (lasttoken == TLP && app == &args->narg.next
+					    && rpp == orig_rpp) {
+			/* We have a function */
+			consumetoken(TRP);
+			funclinno = plinno;
+			/*
+			 * - Require plain text.
+			 * - Functions with '/' cannot be called.
+			 * - Reject name=().
+			 * - Reject ksh extended glob patterns.
+			 */
+			if (!noexpand(n->narg.text) || quoteflag ||
+			    strchr(n->narg.text, '/') ||
+			    strchr("!%*+-=?@}~",
+				n->narg.text[strlen(n->narg.text) - 1]))
+				synerror("Bad function name");
+			rmescapes(n->narg.text);
+			if (find_builtin(n->narg.text, &special) >= 0 &&
+			    special)
+				synerror("Cannot override a special builtin with a function");
+			n->type = NDEFUN;
+			n->narg.next = command();
+			funclinno = 0;
+			return n;
+		} else {
+			tokpushback++;
+			break;
+		}
+	}
+	*app = NULL;
+	*rpp = NULL;
+	n = (union node *)stalloc(sizeof (struct ncmd));
+	n->type = NCMD;
+	n->ncmd.args = args;
+	n->ncmd.redirect = redir;
+	return n;
+}
+
+static union node *
+makename(void)
+{
+	union node *n;
+
+	n = (union node *)stalloc(sizeof (struct narg));
+	n->type = NARG;
+	n->narg.next = NULL;
+	n->narg.text = wordtext;
+	n->narg.backquote = backquotelist;
+	return n;
+}
+
+static union node *
+makebinary(int type, union node *n1, union node *n2)
+{
+	union node *n;
+
+	n = (union node *)stalloc(sizeof (struct nbinary));
+	n->type = type;
+	n->nbinary.ch1 = n1;
+	n->nbinary.ch2 = n2;
+	return (n);
+}
+
+void
+forcealias(void)
+{
+	checkkwd |= CHKALIAS;
+}
+
+void
+fixredir(union node *n, const char *text, int err)
+{
+	TRACE(("Fix redir %s %d\n", text, err));
+	if (!err)
+		n->ndup.vname = NULL;
+
+	if (is_digit(text[0]) && text[1] == '\0')
+		n->ndup.dupfd = digit_val(text[0]);
+	else if (text[0] == '-' && text[1] == '\0')
+		n->ndup.dupfd = -1;
+	else {
+
+		if (err)
+			synerror("Bad fd number");
+		else
+			n->ndup.vname = makename();
+	}
+}
+
+
+static void
+parsefname(void)
+{
+	union node *n = redirnode;
+
+	consumetoken(TWORD);
+	if (n->type == NHERE) {
+		struct heredoc *here = heredoc;
+		struct heredoc *p;
+
+		if (quoteflag == 0)
+			n->type = NXHERE;
+		TRACE(("Here document %d\n", n->type));
+		if (here->striptabs) {
+			while (*wordtext == '\t')
+				wordtext++;
+		}
+		if (! noexpand(wordtext))
+			synerror("Illegal eof marker for << redirection");
+		rmescapes(wordtext);
+		here->eofmark = wordtext;
+		here->next = NULL;
+		if (heredoclist == NULL)
+			heredoclist = here;
+		else {
+			for (p = heredoclist ; p->next ; p = p->next);
+			p->next = here;
+		}
+	} else if (n->type == NTOFD || n->type == NFROMFD) {
+		fixredir(n, wordtext, 0);
+	} else {
+		n->nfile.fname = makename();
+	}
+}
+
+
+/*
+ * Input any here documents.
+ */
+
+static void
+parseheredoc(void)
+{
+	struct heredoc *here;
+	union node *n;
+
+	while (heredoclist) {
+		here = heredoclist;
+		heredoclist = here->next;
+		if (needprompt) {
+			setprompt(2);
+			needprompt = 0;
+		}
+		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
+				here->eofmark, here->striptabs);
+		n = makename();
+		here->here->nhere.doc = n;
+	}
+}
+
+static int
+peektoken(void)
+{
+	int t;
+
+	t = readtoken();
+	tokpushback++;
+	return (t);
+}
+
+static int
+readtoken(void)
+{
+	int t;
+	struct alias *ap;
+#ifdef DEBUG
+	int alreadyseen = tokpushback;
+#endif
+
+	top:
+	t = xxreadtoken();
+
+	/*
+	 * eat newlines
+	 */
+	if (checkkwd & CHKNL) {
+		while (t == TNL) {
+			parseheredoc();
+			t = xxreadtoken();
+		}
+	}
+
+	/*
+	 * check for keywords and aliases
+	 */
+	if (t == TWORD && !quoteflag)
+	{
+		const char * const *pp;
+
+		if (checkkwd & CHKKWD)
+			for (pp = parsekwd; *pp; pp++) {
+				if (**pp == *wordtext && equal(*pp, wordtext))
+				{
+					lasttoken = t = pp - parsekwd + KWDOFFSET;
+					TRACE(("keyword %s recognized\n", tokname[t]));
+					goto out;
+				}
+			}
+		if (checkkwd & CHKALIAS &&
+		    (ap = lookupalias(wordtext, 1)) != NULL) {
+			pushstring(ap->val, strlen(ap->val), ap);
+			goto top;
+		}
+	}
+out:
+	if (t != TNOT)
+		checkkwd = 0;
+
+#ifdef DEBUG
+	if (!alreadyseen)
+	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
+	else
+	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
+#endif
+	return (t);
+}
+
+
+/*
+ * Read the next input token.
+ * If the token is a word, we set backquotelist to the list of cmds in
+ *	backquotes.  We set quoteflag to true if any part of the word was
+ *	quoted.
+ * If the token is TREDIR, then we set redirnode to a structure containing
+ *	the redirection.
+ * In all cases, the variable startlinno is set to the number of the line
+ *	on which the token starts.
+ *
+ * [Change comment:  here documents and internal procedures]
+ * [Readtoken shouldn't have any arguments.  Perhaps we should make the
+ *  word parsing code into a separate routine.  In this case, readtoken
+ *  doesn't need to have any internal procedures, but parseword does.
+ *  We could also make parseoperator in essence the main routine, and
+ *  have parseword (readtoken1?) handle both words and redirection.]
+ */
+
+#define RETURN(token)	return lasttoken = token
+
+static int
+xxreadtoken(void)
+{
+	int c;
+
+	if (tokpushback) {
+		tokpushback = 0;
+		return lasttoken;
+	}
+	if (needprompt) {
+		setprompt(2);
+		needprompt = 0;
+	}
+	startlinno = plinno;
+	for (;;) {	/* until token or start of word found */
+		c = pgetc_macro();
+		switch (c) {
+		case ' ': case '\t':
+			continue;
+		case '#':
+			while ((c = pgetc()) != '\n' && c != PEOF);
+			pungetc();
+			continue;
+		case '\\':
+			if (pgetc() == '\n') {
+				startlinno = ++plinno;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				continue;
+			}
+			pungetc();
+			/* FALLTHROUGH */
+		default:
+			return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
+		case '\n':
+			plinno++;
+			needprompt = doprompt;
+			RETURN(TNL);
+		case PEOF:
+			RETURN(TEOF);
+		case '&':
+			if (pgetc_linecont() == '&')
+				RETURN(TAND);
+			pungetc();
+			RETURN(TBACKGND);
+		case '|':
+			if (pgetc_linecont() == '|')
+				RETURN(TOR);
+			pungetc();
+			RETURN(TPIPE);
+		case ';':
+			c = pgetc_linecont();
+			if (c == ';')
+				RETURN(TENDCASE);
+			else if (c == '&')
+				RETURN(TFALLTHRU);
+			pungetc();
+			RETURN(TSEMI);
+		case '(':
+			RETURN(TLP);
+		case ')':
+			RETURN(TRP);
+		}
+	}
+#undef RETURN
+}
+
+
+#define MAXNEST_static 8
+struct tokenstate
+{
+	const char *syntax; /* *SYNTAX */
+	int parenlevel; /* levels of parentheses in arithmetic */
+	enum tokenstate_category
+	{
+		TSTATE_TOP,
+		TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
+		TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
+		TSTATE_ARITH
+	} category;
+};
+
+
+/*
+ * Check to see whether we are at the end of the here document.  When this
+ * is called, c is set to the first character of the next input line.  If
+ * we are at the end of the here document, this routine sets the c to PEOF.
+ * The new value of c is returned.
+ */
+
+static int
+checkend(int c, const char *eofmark, int striptabs)
+{
+	if (striptabs) {
+		while (c == '\t')
+			c = pgetc();
+	}
+	if (c == *eofmark) {
+		int c2;
+		const char *q;
+
+		for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
+			;
+		if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
+			c = PEOF;
+			if (c2 == '\n') {
+				plinno++;
+				needprompt = doprompt;
+			}
+		} else {
+			pungetc();
+			pushstring(eofmark + 1, q - (eofmark + 1), NULL);
+		}
+	} else if (c == '\n' && *eofmark == '\0') {
+		c = PEOF;
+		plinno++;
+		needprompt = doprompt;
+	}
+	return (c);
+}
+
+
+/*
+ * Parse a redirection operator.  The variable "out" points to a string
+ * specifying the fd to be redirected.  The variable "c" contains the
+ * first character of the redirection operator.
+ */
+
+static void
+parseredir(char *out, int c)
+{
+	char fd = *out;
+	union node *np;
+
+	np = (union node *)stalloc(sizeof (struct nfile));
+	if (c == '>') {
+		np->nfile.fd = 1;
+		c = pgetc_linecont();
+		if (c == '>')
+			np->type = NAPPEND;
+		else if (c == '&')
+			np->type = NTOFD;
+		else if (c == '|')
+			np->type = NCLOBBER;
+		else {
+			np->type = NTO;
+			pungetc();
+		}
+	} else {	/* c == '<' */
+		np->nfile.fd = 0;
+		c = pgetc_linecont();
+		if (c == '<') {
+			if (sizeof (struct nfile) != sizeof (struct nhere)) {
+				np = (union node *)stalloc(sizeof (struct nhere));
+				np->nfile.fd = 0;
+			}
+			np->type = NHERE;
+			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
+			heredoc->here = np;
+			if ((c = pgetc_linecont()) == '-') {
+				heredoc->striptabs = 1;
+			} else {
+				heredoc->striptabs = 0;
+				pungetc();
+			}
+		} else if (c == '&')
+			np->type = NFROMFD;
+		else if (c == '>')
+			np->type = NFROMTO;
+		else {
+			np->type = NFROM;
+			pungetc();
+		}
+	}
+	if (fd != '\0')
+		np->nfile.fd = digit_val(fd);
+	redirnode = np;
+}
+
+/*
+ * Called to parse command substitutions.
+ */
+
+static char *
+parsebackq(char *out, struct nodelist **pbqlist,
+		int oldstyle, int dblquote, int quoted)
+{
+	struct nodelist **nlpp;
+	union node *n;
+	char *volatile str;
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	size_t savelen;
+	int saveprompt;
+	const int bq_startlinno = plinno;
+	char *volatile ostr = NULL;
+	struct parsefile *const savetopfile = getcurrentfile();
+	struct heredoc *const saveheredoclist = heredoclist;
+	struct heredoc *here;
+
+	str = NULL;
+	if (setjmp(jmploc.loc)) {
+		popfilesupto(savetopfile);
+		if (str)
+			ckfree(str);
+		if (ostr)
+			ckfree(ostr);
+		heredoclist = saveheredoclist;
+		handler = savehandler;
+		if (exception == EXERROR) {
+			startlinno = bq_startlinno;
+			synerror("Error in command substitution");
+		}
+		longjmp(handler->loc, 1);
+	}
+	INTOFF;
+	savelen = out - stackblock();
+	if (savelen > 0) {
+		str = ckmalloc(savelen);
+		memcpy(str, stackblock(), savelen);
+	}
+	handler = &jmploc;
+	heredoclist = NULL;
+	INTON;
+        if (oldstyle) {
+                /* We must read until the closing backquote, giving special
+                   treatment to some slashes, and then push the string and
+                   reread it as input, interpreting it normally.  */
+                char *oout;
+                int c;
+                int olen;
+
+
+                STARTSTACKSTR(oout);
+		for (;;) {
+			if (needprompt) {
+				setprompt(2);
+				needprompt = 0;
+			}
+			CHECKSTRSPACE(2, oout);
+			c = pgetc_linecont();
+			if (c == '`')
+				break;
+			switch (c) {
+			case '\\':
+				c = pgetc();
+                                if (c != '\\' && c != '`' && c != '$'
+                                    && (!dblquote || c != '"'))
+                                        USTPUTC('\\', oout);
+				break;
+
+			case '\n':
+				plinno++;
+				needprompt = doprompt;
+				break;
+
+			case PEOF:
+			        startlinno = plinno;
+				synerror("EOF in backquote substitution");
+ 				break;
+
+			default:
+				break;
+			}
+			USTPUTC(c, oout);
+                }
+                USTPUTC('\0', oout);
+                olen = oout - stackblock();
+		INTOFF;
+		ostr = ckmalloc(olen);
+		memcpy(ostr, stackblock(), olen);
+		setinputstring(ostr, 1);
+		INTON;
+        }
+	nlpp = pbqlist;
+	while (*nlpp)
+		nlpp = &(*nlpp)->next;
+	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+	(*nlpp)->next = NULL;
+
+	if (oldstyle) {
+		saveprompt = doprompt;
+		doprompt = 0;
+	}
+
+	n = list(0);
+
+	if (oldstyle) {
+		if (peektoken() != TEOF)
+			synexpect(-1);
+		doprompt = saveprompt;
+	} else
+		consumetoken(TRP);
+
+	(*nlpp)->n = n;
+        if (oldstyle) {
+		/*
+		 * Start reading from old file again, ignoring any pushed back
+		 * tokens left from the backquote parsing
+		 */
+                popfile();
+		tokpushback = 0;
+	}
+	STARTSTACKSTR(out);
+	CHECKSTRSPACE(savelen + 1, out);
+	INTOFF;
+	if (str) {
+		memcpy(out, str, savelen);
+		STADJUST(savelen, out);
+		ckfree(str);
+		str = NULL;
+	}
+	if (ostr) {
+		ckfree(ostr);
+		ostr = NULL;
+	}
+	here = saveheredoclist;
+	if (here != NULL) {
+		while (here->next != NULL)
+			here = here->next;
+		here->next = heredoclist;
+		heredoclist = saveheredoclist;
+	}
+	handler = savehandler;
+	INTON;
+	if (quoted)
+		USTPUTC(CTLBACKQ | CTLQUOTE, out);
+	else
+		USTPUTC(CTLBACKQ, out);
+	return out;
+}
+
+
+/*
+ * Called to parse a backslash escape sequence inside $'...'.
+ * The backslash has already been read.
+ */
+static char *
+readcstyleesc(char *out)
+{
+	int c, vc, i, n;
+	unsigned int v;
+
+	c = pgetc();
+	switch (c) {
+	case '\0':
+		synerror("Unterminated quoted string");
+	case '\n':
+		plinno++;
+		if (doprompt)
+			setprompt(2);
+		else
+			setprompt(0);
+		return out;
+	case '\\':
+	case '\'':
+	case '"':
+		v = c;
+		break;
+	case 'a': v = '\a'; break;
+	case 'b': v = '\b'; break;
+	case 'e': v = '\033'; break;
+	case 'f': v = '\f'; break;
+	case 'n': v = '\n'; break;
+	case 'r': v = '\r'; break;
+	case 't': v = '\t'; break;
+	case 'v': v = '\v'; break;
+	case 'x':
+		  v = 0;
+		  for (;;) {
+			  c = pgetc();
+			  if (c >= '0' && c <= '9')
+				  v = (v << 4) + c - '0';
+			  else if (c >= 'A' && c <= 'F')
+				  v = (v << 4) + c - 'A' + 10;
+			  else if (c >= 'a' && c <= 'f')
+				  v = (v << 4) + c - 'a' + 10;
+			  else
+				  break;
+		  }
+		  pungetc();
+		  break;
+	case '0': case '1': case '2': case '3':
+	case '4': case '5': case '6': case '7':
+		  v = c - '0';
+		  c = pgetc();
+		  if (c >= '0' && c <= '7') {
+			  v <<= 3;
+			  v += c - '0';
+			  c = pgetc();
+			  if (c >= '0' && c <= '7') {
+				  v <<= 3;
+				  v += c - '0';
+			  } else
+				  pungetc();
+		  } else
+			  pungetc();
+		  break;
+	case 'c':
+		  c = pgetc();
+		  if (c < 0x3f || c > 0x7a || c == 0x60)
+			  synerror("Bad escape sequence");
+		  if (c == '\\' && pgetc() != '\\')
+			  synerror("Bad escape sequence");
+		  if (c == '?')
+			  v = 127;
+		  else
+			  v = c & 0x1f;
+		  break;
+	case 'u':
+	case 'U':
+		  n = c == 'U' ? 8 : 4;
+		  v = 0;
+		  for (i = 0; i < n; i++) {
+			  c = pgetc();
+			  if (c >= '0' && c <= '9')
+				  v = (v << 4) + c - '0';
+			  else if (c >= 'A' && c <= 'F')
+				  v = (v << 4) + c - 'A' + 10;
+			  else if (c >= 'a' && c <= 'f')
+				  v = (v << 4) + c - 'a' + 10;
+			  else
+				  synerror("Bad escape sequence");
+		  }
+		  if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
+			  synerror("Bad escape sequence");
+		  /* We really need iconv here. */
+		  if (initial_localeisutf8 && v > 127) {
+			  CHECKSTRSPACE(4, out);
+			  /*
+			   * We cannot use wctomb() as the locale may have
+			   * changed.
+			   */
+			  if (v <= 0x7ff) {
+				  USTPUTC(0xc0 | v >> 6, out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  } else if (v <= 0xffff) {
+				  USTPUTC(0xe0 | v >> 12, out);
+				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  } else if (v <= 0x10ffff) {
+				  USTPUTC(0xf0 | v >> 18, out);
+				  USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
+				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  }
+		  }
+		  if (v > 127)
+			  v = '?';
+		  break;
+	default:
+		  synerror("Bad escape sequence");
+	}
+	vc = (char)v;
+	/*
+	 * We can't handle NUL bytes.
+	 * POSIX says we should skip till the closing quote.
+	 */
+	if (vc == '\0') {
+		while ((c = pgetc()) != '\'') {
+			if (c == '\\')
+				c = pgetc();
+			if (c == PEOF)
+				synerror("Unterminated quoted string");
+			if (c == '\n') {
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+			}
+		}
+		pungetc();
+		return out;
+	}
+	if (SQSYNTAX[vc] == CCTL)
+		USTPUTC(CTLESC, out);
+	USTPUTC(vc, out);
+	return out;
+}
+
+
+/*
+ * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
+ * is not NULL, read a here document.  In the latter case, eofmark is the
+ * word which marks the end of the document and striptabs is true if
+ * leading tabs should be stripped from the document.  The argument firstc
+ * is the first character of the input token or document.
+ *
+ * Because C does not have internal subroutines, I have simulated them
+ * using goto's to implement the subroutine linkage.  The following macros
+ * will run code that appears at the end of readtoken1.
+ */
+
+#define PARSESUB()	{goto parsesub; parsesub_return:;}
+#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
+
+static int
+readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
+    int striptabs)
+{
+	int c = firstc;
+	char *out;
+	int len;
+	struct nodelist *bqlist;
+	int quotef;
+	int newvarnest;
+	int level;
+	int synentry;
+	struct tokenstate state_static[MAXNEST_static];
+	int maxnest = MAXNEST_static;
+	struct tokenstate *state = state_static;
+	int sqiscstyle = 0;
+
+	startlinno = plinno;
+	quotef = 0;
+	bqlist = NULL;
+	newvarnest = 0;
+	level = 0;
+	state[level].syntax = initialsyntax;
+	state[level].parenlevel = 0;
+	state[level].category = TSTATE_TOP;
+
+	STARTSTACKSTR(out);
+	loop: {	/* for each line, until end of word */
+		if (eofmark && eofmark != NOEOFMARK)
+			/* set c to PEOF if at end of here document */
+			c = checkend(c, eofmark, striptabs);
+		for (;;) {	/* until end of line or end of word */
+			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
+
+			synentry = state[level].syntax[c];
+
+			switch(synentry) {
+			case CNL:	/* '\n' */
+				if (level == 0)
+					goto endword;	/* exit outer loop */
+				/* FALLTHROUGH */
+			case CQNL:
+				USTPUTC(c, out);
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				c = pgetc();
+				goto loop;		/* continue outer loop */
+			case CSBACK:
+				if (sqiscstyle) {
+					out = readcstyleesc(out);
+					break;
+				}
+				/* FALLTHROUGH */
+			case CWORD:
+				USTPUTC(c, out);
+				break;
+			case CCTL:
+				if (eofmark == NULL || initialsyntax != SQSYNTAX)
+					USTPUTC(CTLESC, out);
+				USTPUTC(c, out);
+				break;
+			case CBACK:	/* backslash */
+				c = pgetc();
+				if (c == PEOF) {
+					USTPUTC('\\', out);
+					pungetc();
+				} else if (c == '\n') {
+					plinno++;
+					if (doprompt)
+						setprompt(2);
+					else
+						setprompt(0);
+				} else {
+					if (state[level].syntax == DQSYNTAX &&
+					    c != '\\' && c != '`' && c != '$' &&
+					    (c != '"' || (eofmark != NULL &&
+						newvarnest == 0)) &&
+					    (c != '}' || state[level].category != TSTATE_VAR_OLD))
+						USTPUTC('\\', out);
+					if ((eofmark == NULL ||
+					    newvarnest > 0) &&
+					    state[level].syntax == BASESYNTAX)
+						USTPUTC(CTLQUOTEMARK, out);
+					if (SQSYNTAX[c] == CCTL)
+						USTPUTC(CTLESC, out);
+					USTPUTC(c, out);
+					if ((eofmark == NULL ||
+					    newvarnest > 0) &&
+					    state[level].syntax == BASESYNTAX &&
+					    state[level].category == TSTATE_VAR_OLD)
+						USTPUTC(CTLQUOTEEND, out);
+					quotef++;
+				}
+				break;
+			case CSQUOTE:
+				USTPUTC(CTLQUOTEMARK, out);
+				state[level].syntax = SQSYNTAX;
+				sqiscstyle = 0;
+				break;
+			case CDQUOTE:
+				USTPUTC(CTLQUOTEMARK, out);
+				state[level].syntax = DQSYNTAX;
+				break;
+			case CENDQUOTE:
+				if (eofmark != NULL && newvarnest == 0)
+					USTPUTC(c, out);
+				else {
+					if (state[level].category == TSTATE_VAR_OLD)
+						USTPUTC(CTLQUOTEEND, out);
+					state[level].syntax = BASESYNTAX;
+					quotef++;
+				}
+				break;
+			case CVAR:	/* '$' */
+				PARSESUB();		/* parse substitution */
+				break;
+			case CENDVAR:	/* '}' */
+				if (level > 0 &&
+				    ((state[level].category == TSTATE_VAR_OLD &&
+				      state[level].syntax ==
+				      state[level - 1].syntax) ||
+				    (state[level].category == TSTATE_VAR_NEW &&
+				     state[level].syntax == BASESYNTAX))) {
+					if (state[level].category == TSTATE_VAR_NEW)
+						newvarnest--;
+					level--;
+					USTPUTC(CTLENDVAR, out);
+				} else {
+					USTPUTC(c, out);
+				}
+				break;
+			case CLP:	/* '(' in arithmetic */
+				state[level].parenlevel++;
+				USTPUTC(c, out);
+				break;
+			case CRP:	/* ')' in arithmetic */
+				if (state[level].parenlevel > 0) {
+					USTPUTC(c, out);
+					--state[level].parenlevel;
+				} else {
+					if (pgetc_linecont() == ')') {
+						if (level > 0 &&
+						    state[level].category == TSTATE_ARITH) {
+							level--;
+							USTPUTC(CTLENDARI, out);
+						} else
+							USTPUTC(')', out);
+					} else {
+						/*
+						 * unbalanced parens
+						 *  (don't 2nd guess - no error)
+						 */
+						pungetc();
+						USTPUTC(')', out);
+					}
+				}
+				break;
+			case CBQUOTE:	/* '`' */
+				out = parsebackq(out, &bqlist, 1,
+				    state[level].syntax == DQSYNTAX &&
+				    (eofmark == NULL || newvarnest > 0),
+				    state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
+				break;
+			case CEOF:
+				goto endword;		/* exit outer loop */
+			case CIGN:
+				break;
+			default:
+				if (level == 0)
+					goto endword;	/* exit outer loop */
+				USTPUTC(c, out);
+			}
+			c = pgetc_macro();
+		}
+	}
+endword:
+	if (state[level].syntax == ARISYNTAX)
+		synerror("Missing '))'");
+	if (state[level].syntax != BASESYNTAX && eofmark == NULL)
+		synerror("Unterminated quoted string");
+	if (state[level].category == TSTATE_VAR_OLD ||
+	    state[level].category == TSTATE_VAR_NEW) {
+		startlinno = plinno;
+		synerror("Missing '}'");
+	}
+	if (state != state_static)
+		parser_temp_free_upto(state);
+	USTPUTC('\0', out);
+	len = out - stackblock();
+	out = stackblock();
+	if (eofmark == NULL) {
+		if ((c == '>' || c == '<')
+		 && quotef == 0
+		 && len <= 2
+		 && (*out == '\0' || is_digit(*out))) {
+			parseredir(out, c);
+			return lasttoken = TREDIR;
+		} else {
+			pungetc();
+		}
+	}
+	quoteflag = quotef;
+	backquotelist = bqlist;
+	grabstackblock(len);
+	wordtext = out;
+	return lasttoken = TWORD;
+/* end of readtoken routine */
+
+
+/*
+ * Parse a substitution.  At this point, we have read the dollar sign
+ * and nothing else.
+ */
+
+parsesub: {
+	int subtype;
+	int typeloc;
+	int flags;
+	char *p;
+	static const char types[] = "}-+?=";
+	int linno;
+	int length;
+	int c1;
+
+	c = pgetc_linecont();
+	if (c == '(') {	/* $(command) or $((arith)) */
+		if (pgetc_linecont() == '(') {
+			PARSEARITH();
+		} else {
+			pungetc();
+			out = parsebackq(out, &bqlist, 0,
+			    state[level].syntax == DQSYNTAX &&
+			    (eofmark == NULL || newvarnest > 0),
+			    state[level].syntax == DQSYNTAX ||
+			    state[level].syntax == ARISYNTAX);
+		}
+	} else if (c == '{' || is_name(c) || is_special(c)) {
+		USTPUTC(CTLVAR, out);
+		typeloc = out - stackblock();
+		USTPUTC(VSNORMAL, out);
+		subtype = VSNORMAL;
+		flags = 0;
+		if (c == '{') {
+			c = pgetc_linecont();
+			subtype = 0;
+		}
+varname:
+		if (!is_eof(c) && is_name(c)) {
+			length = 0;
+			do {
+				STPUTC(c, out);
+				c = pgetc_linecont();
+				length++;
+			} while (!is_eof(c) && is_in_name(c));
+			if (length == 6 &&
+			    strncmp(out - length, "LINENO", length) == 0) {
+				/* Replace the variable name with the
+				 * current line number. */
+				STADJUST(-6, out);
+				CHECKSTRSPACE(11, out);
+				linno = plinno;
+				if (funclinno != 0)
+					linno -= funclinno - 1;
+				length = snprintf(out, 11, "%d", linno);
+				if (length > 10)
+					length = 10;
+				out += length;
+				flags |= VSLINENO;
+			}
+		} else if (is_digit(c)) {
+			if (subtype != VSNORMAL) {
+				do {
+					STPUTC(c, out);
+					c = pgetc_linecont();
+				} while (is_digit(c));
+			} else {
+				USTPUTC(c, out);
+				c = pgetc_linecont();
+			}
+		} else if (is_special(c)) {
+			c1 = c;
+			c = pgetc_linecont();
+			if (subtype == 0 && c1 == '#') {
+				subtype = VSLENGTH;
+				if (strchr(types, c) == NULL && c != ':' &&
+				    c != '#' && c != '%')
+					goto varname;
+				c1 = c;
+				c = pgetc_linecont();
+				if (c1 != '}' && c == '}') {
+					pungetc();
+					c = c1;
+					goto varname;
+				}
+				pungetc();
+				c = c1;
+				c1 = '#';
+				subtype = 0;
+			}
+			USTPUTC(c1, out);
+		} else {
+			subtype = VSERROR;
+			if (c == '}')
+				pungetc();
+			else if (c == '\n' || c == PEOF)
+				synerror("Unexpected end of line in substitution");
+			else if (BASESYNTAX[c] != CCTL)
+				USTPUTC(c, out);
+		}
+		if (subtype == 0) {
+			switch (c) {
+			case ':':
+				flags |= VSNUL;
+				c = pgetc_linecont();
+				/*FALLTHROUGH*/
+			default:
+				p = strchr(types, c);
+				if (p == NULL) {
+					if (c == '\n' || c == PEOF)
+						synerror("Unexpected end of line in substitution");
+					if (flags == VSNUL)
+						STPUTC(':', out);
+					if (BASESYNTAX[c] != CCTL)
+						STPUTC(c, out);
+					subtype = VSERROR;
+				} else
+					subtype = p - types + VSNORMAL;
+				break;
+			case '%':
+			case '#':
+				{
+					int cc = c;
+					subtype = c == '#' ? VSTRIMLEFT :
+							     VSTRIMRIGHT;
+					c = pgetc_linecont();
+					if (c == cc)
+						subtype++;
+					else
+						pungetc();
+					break;
+				}
+			}
+		} else if (subtype != VSERROR) {
+			if (subtype == VSLENGTH && c != '}')
+				subtype = VSERROR;
+			pungetc();
+		}
+		STPUTC('=', out);
+		if (state[level].syntax == DQSYNTAX ||
+		    state[level].syntax == ARISYNTAX)
+			flags |= VSQUOTE;
+		*(stackblock() + typeloc) = subtype | flags;
+		if (subtype != VSNORMAL) {
+			if (level + 1 >= maxnest) {
+				maxnest *= 2;
+				if (state == state_static) {
+					state = parser_temp_alloc(
+					    maxnest * sizeof(*state));
+					memcpy(state, state_static,
+					    MAXNEST_static * sizeof(*state));
+				} else
+					state = parser_temp_realloc(state,
+					    maxnest * sizeof(*state));
+			}
+			level++;
+			state[level].parenlevel = 0;
+			if (subtype == VSMINUS || subtype == VSPLUS ||
+			    subtype == VSQUESTION || subtype == VSASSIGN) {
+				/*
+				 * For operators that were in the Bourne shell,
+				 * inherit the double-quote state.
+				 */
+				state[level].syntax = state[level - 1].syntax;
+				state[level].category = TSTATE_VAR_OLD;
+			} else {
+				/*
+				 * The other operators take a pattern,
+				 * so go to BASESYNTAX.
+				 * Also, ' and " are now special, even
+				 * in here documents.
+				 */
+				state[level].syntax = BASESYNTAX;
+				state[level].category = TSTATE_VAR_NEW;
+				newvarnest++;
+			}
+		}
+	} else if (c == '\'' && state[level].syntax == BASESYNTAX) {
+		/* $'cstylequotes' */
+		USTPUTC(CTLQUOTEMARK, out);
+		state[level].syntax = SQSYNTAX;
+		sqiscstyle = 1;
+	} else {
+		USTPUTC('$', out);
+		pungetc();
+	}
+	goto parsesub_return;
+}
+
+
+/*
+ * Parse an arithmetic expansion (indicate start of one and set state)
+ */
+parsearith: {
+
+	if (level + 1 >= maxnest) {
+		maxnest *= 2;
+		if (state == state_static) {
+			state = parser_temp_alloc(
+			    maxnest * sizeof(*state));
+			memcpy(state, state_static,
+			    MAXNEST_static * sizeof(*state));
+		} else
+			state = parser_temp_realloc(state,
+			    maxnest * sizeof(*state));
+	}
+	level++;
+	state[level].syntax = ARISYNTAX;
+	state[level].parenlevel = 0;
+	state[level].category = TSTATE_ARITH;
+	USTPUTC(CTLARI, out);
+	if (state[level - 1].syntax == DQSYNTAX)
+		USTPUTC('"',out);
+	else
+		USTPUTC(' ',out);
+	goto parsearith_return;
+}
+
+} /* end of readtoken */
+
+
+/*
+ * Returns true if the text contains nothing to expand (no dollar signs
+ * or backquotes).
+ */
+
+static int
+noexpand(char *text)
+{
+	char *p;
+	char c;
+
+	p = text;
+	while ((c = *p++) != '\0') {
+		if ( c == CTLQUOTEMARK)
+			continue;
+		if (c == CTLESC)
+			p++;
+		else if (BASESYNTAX[(int)c] == CCTL)
+			return 0;
+	}
+	return 1;
+}
+
+
+/*
+ * Return true if the argument is a legal variable name (a letter or
+ * underscore followed by zero or more letters, underscores, and digits).
+ */
+
+int
+goodname(const char *name)
+{
+	const char *p;
+
+	p = name;
+	if (! is_name(*p))
+		return 0;
+	while (*++p) {
+		if (! is_in_name(*p))
+			return 0;
+	}
+	return 1;
+}
+
+
+int
+isassignment(const char *p)
+{
+	if (!is_name(*p))
+		return 0;
+	p++;
+	for (;;) {
+		if (*p == '=')
+			return 1;
+		else if (!is_in_name(*p))
+			return 0;
+		p++;
+	}
+}
+
+
+static void
+consumetoken(int token)
+{
+	if (readtoken() != token)
+		synexpect(token);
+}
+
+
+/*
+ * Called when an unexpected token is read during the parse.  The argument
+ * is the token that is expected, or -1 if more than one type of token can
+ * occur at this point.
+ */
+
+static void
+synexpect(int token)
+{
+	char msg[64];
+
+	if (token >= 0) {
+		fmtstr(msg, 64, "%s unexpected (expecting %s)",
+			tokname[lasttoken], tokname[token]);
+	} else {
+		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
+	}
+	synerror(msg);
+}
+
+
+static void
+synerror(const char *msg)
+{
+	if (commandname)
+		outfmt(out2, "%s: %d: ", commandname, startlinno);
+	else if (arg0)
+		outfmt(out2, "%s: ", arg0);
+	outfmt(out2, "Syntax error: %s\n", msg);
+	error((char *)NULL);
+}
+
+static void
+setprompt(int which)
+{
+	whichprompt = which;
+	if (which == 0)
+		return;
+
+	if (which == 1 && *ps0val()) {
+		out2str(expandprompt(ps0val()));
+		flushout(out2);
+	}
+
+#ifndef NO_HISTORY
+	if (!el)
+#endif
+	{
+		out2str(getprompt(NULL));
+		flushout(out2);
+	}
+}
+
+static int
+pgetc_linecont(void)
+{
+	int c;
+
+	while ((c = pgetc_macro()) == '\\') {
+		c = pgetc();
+		if (c == '\n') {
+			plinno++;
+			if (doprompt)
+				setprompt(2);
+			else
+				setprompt(0);
+		} else {
+			pungetc();
+			/* Allow the backslash to be pushed back. */
+			pushstring("\\", 1, NULL);
+			return (pgetc());
+		}
+	}
+	return (c);
+}
+
+static char *
+expandprompt(const char *fmt) {
+	static char ps[PROMPTLEN];
+	const char *pwd, *home;
+	int i, trim;
+
+	/*
+	 * Format prompt string.
+	 */
+	for (i = 0; (i < PROMPTLEN - 1) && (*fmt != '\0'); i++, fmt++)
+		if (*fmt == '\\')
+			switch (*++fmt) {
+
+				/*
+				 * Hostname.
+				 *
+				 * \h specifies just the local hostname,
+				 * \H specifies fully-qualified hostname.
+				 */
+			case 'h':
+			case 'H':
+				ps[i] = '\0';
+				gethostname(&ps[i], PROMPTLEN - i - 1);
+				ps[PROMPTLEN - 1] = '\0';
+				/* Skip to end of hostname. */
+				trim = (*fmt == 'h') ? '.' : '\0';
+				while ((ps[i] != '\0') && (ps[i] != trim))
+					i++;
+				--i;
+				break;
+
+				/*
+				 * Working directory.
+				 *
+				 * \W specifies just the final component,
+				 * \w specifies the entire path.
+				 */
+			case 'W':
+			case 'w':
+				pwd = lookupvar("PWD");
+				home = lookupvar("HOME");
+				if (pwd == NULL || *pwd == '\0')
+					pwd = "?";
+				if (home == NULL || *home == '\0')
+					home = "?";
+				if (*fmt == 'W' &&
+				    *pwd == '/' && pwd[1] != '\0' &&
+					strcmp(pwd, home) != 0) {
+					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
+					    PROMPTLEN - i);
+				} else {
+					if (strncmp(pwd, home, strlen(home)) == 0) {
+						ps[i++] = '~';
+						pwd += strlen(home);
+					}
+					strlcpy(&ps[i], pwd, PROMPTLEN - i);
+				}
+				/* Skip to end of path. */
+				while (ps[i] != '\0')
+					i++;
+				--i;
+				break;
+
+				/*
+				 * Exit status if non-zero.
+				 */
+			case '?':
+				if (exitstatus != 0) {
+					snprintf(&ps[i], PROMPTLEN - i, "%d", exitstatus);
+					while (ps[i] != '\0')
+						i++;
+				}
+				i--;
+				break;
+
+				/*
+				 * Superuser status.
+				 *
+				 * '$' for normal users, '#' for root.
+				 */
+			case '$':
+				ps[i] = (geteuid() != 0) ? '$' : '#';
+				break;
+
+				/*
+				 * A literal \.
+				 */
+			case '\\':
+				ps[i] = '\\';
+				break;
+
+				/*
+				 * Emit unrecognized formats verbatim.
+				 */
+			default:
+				ps[i] = '\\';
+				if (i < PROMPTLEN - 2)
+					ps[++i] = *fmt;
+				break;
+			}
+		else
+			ps[i] = *fmt;
+	ps[i] = '\0';
+	return (ps);
+}
+
+/*
+ * called by editline -- any expansions to the prompt
+ *    should be added here.
+ */
+char *
+getprompt(void *unused __unused)
+{
+	const char *fmt;
+	static char internal_error[] = "??";
+
+	/*
+	 * Select prompt format.
+	 */
+	switch (whichprompt) {
+	case 0:
+		fmt = "";
+		break;
+	case 1:
+		fmt = ps1val();
+		break;
+	case 2:
+		fmt = ps2val();
+		break;
+	default:
+		return internal_error;
+	}
+
+	return expandprompt(fmt);
+}
+
+char *
+getrprompt(void *unused __unused)
+{
+	const char *fmt;
+	static char internal_error[] = "??";
+
+	/*
+	 * Select prompt format.
+	 */
+	switch (whichprompt) {
+	case 0:
+		fmt = "";
+		break;
+	case 1:
+		fmt = rps1val();
+		break;
+	case 2:
+		fmt = rps2val();
+		break;
+	default:
+		return internal_error;
+	}
+
+	return expandprompt(fmt);
+}
+
+
+const char *
+expandstr(const char *ps)
+{
+	union node n;
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	const int saveprompt = doprompt;
+	struct parsefile *const savetopfile = getcurrentfile();
+	struct parser_temp *const saveparser_temp = parser_temp;
+	const char *result = NULL;
+
+	if (!setjmp(jmploc.loc)) {
+		handler = &jmploc;
+		parser_temp = NULL;
+		setinputstring(ps, 1);
+		doprompt = 0;
+		readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
+		if (backquotelist != NULL)
+			error("Command substitution not allowed here");
+
+		n.narg.type = NARG;
+		n.narg.next = NULL;
+		n.narg.text = wordtext;
+		n.narg.backquote = backquotelist;
+
+		expandarg(&n, NULL, 0);
+		result = stackblock();
+		INTOFF;
+	}
+	handler = savehandler;
+	doprompt = saveprompt;
+	popfilesupto(savetopfile);
+	if (parser_temp != saveparser_temp) {
+		parser_temp_free_all();
+		parser_temp = saveparser_temp;
+	}
+	if (result != NULL) {
+		INTON;
+	} else if (exception == EXINT)
+		raise(SIGINT);
+	return result;
+}
diff --git a/bin/1sh/parser.h b/bin/1sh/parser.h
new file mode 100644
index 00000000..171bc994
--- /dev/null
+++ b/bin/1sh/parser.h
@@ -0,0 +1,88 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)parser.h	8.3 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/parser.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+/* control characters in argument strings */
+#define CTLESC '\300'
+#define CTLVAR '\301'
+#define CTLENDVAR '\371'
+#define CTLBACKQ '\372'
+#define CTLQUOTE 01		/* ored with CTLBACKQ code if in quotes */
+/*	CTLBACKQ | CTLQUOTE == '\373' */
+#define	CTLARI	'\374'
+#define	CTLENDARI '\375'
+#define	CTLQUOTEMARK '\376'
+#define	CTLQUOTEEND '\377' /* only for ${v+-...} */
+
+/* variable substitution byte (follows CTLVAR) */
+#define VSTYPE		0x0f	/* type of variable substitution */
+#define VSNUL		0x10	/* colon--treat the empty string as unset */
+#define VSLINENO	0x20	/* expansion of $LINENO, the line number \
+				   follows immediately */
+#define VSQUOTE		0x80	/* inside double quotes--suppress splitting */
+
+/* values of VSTYPE field */
+#define VSNORMAL	0x1		/* normal variable:  $var or ${var} */
+#define VSMINUS		0x2		/* ${var-text} */
+#define VSPLUS		0x3		/* ${var+text} */
+#define VSQUESTION	0x4		/* ${var?message} */
+#define VSASSIGN	0x5		/* ${var=text} */
+#define VSTRIMLEFT	0x6		/* ${var#pattern} */
+#define VSTRIMLEFTMAX	0x7		/* ${var##pattern} */
+#define VSTRIMRIGHT	0x8		/* ${var%pattern} */
+#define VSTRIMRIGHTMAX 	0x9		/* ${var%%pattern} */
+#define VSLENGTH	0xa		/* ${#var} */
+#define VSERROR		0xb		/* Syntax error, issue when expanded */
+
+
+/*
+ * NEOF is returned by parsecmd when it encounters an end of file.  It
+ * must be distinct from NULL.
+ */
+#define NEOF ((union node *)-1)
+extern int whichprompt;		/* 1 == PS1, 2 == PS2 */
+extern const char *const parsekwd[];
+
+
+union node *parsecmd(int);
+union node *parsewordexp(void);
+void forcealias(void);
+void fixredir(union node *, const char *, int);
+int goodname(const char *);
+int isassignment(const char *);
+char *getprompt(void *);
+char *getrprompt(void *);
+const char *expandstr(const char *);
diff --git a/bin/1sh/printf.c b/bin/1sh/printf.c
new file mode 100644
index 00000000..2545fb62
--- /dev/null
+++ b/bin/1sh/printf.c
@@ -0,0 +1,686 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+ * Copyright 2014 Garrett D'Amore <garrett@damore.org>
+ * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * Important: This file is used both as a standalone program /usr/bin/printf
+ * and as a builtin for /bin/sh (#define SHELL).
+ */
+
+#ifndef SHELL
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1989, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+#endif
+
+#if 0
+static char const sccsid[] = "@(#)printf.c	8.1 (Berkeley) 7/20/93";
+static const char rcsid[] =
+  "$FreeBSD: releng/12.1/usr.bin/printf/printf.c 337618 2018-08-11 11:13:34Z jilles $";
+#endif
+
+#include <sys/types.h>
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wchar.h>
+
+#ifdef SHELL
+#define	main printfcmd
+#include "bltin.h"
+#include "options.h"
+#endif
+
+#define	PF(f, func) do {						\
+	if (havewidth)							\
+		if (haveprec)						\
+			(void)printf(f, fieldwidth, precision, func);	\
+		else							\
+			(void)printf(f, fieldwidth, func);		\
+	else if (haveprec)						\
+		(void)printf(f, precision, func);			\
+	else								\
+		(void)printf(f, func);					\
+} while (0)
+
+static int	 asciicode(void);
+static char	*printf_doformat(char *, int *);
+static int	 escape(char *, int, size_t *);
+static int	 getchr(void);
+static int	 getfloating(long double *, int);
+static int	 getint(int *);
+static int	 getnum(intmax_t *, uintmax_t *, int);
+static const char
+		*getstr(void);
+static char	*mknum(char *, char);
+static void	 usage(void);
+
+static const char digits[] = "0123456789";
+
+static char end_fmt[1];
+
+static int  myargc;
+static char **myargv;
+static char **gargv;
+static char **maxargv;
+
+int
+main(int argc, char *argv[])
+{
+	size_t len;
+	int end, rval;
+	char *format, *fmt, *start;
+#ifndef SHELL
+	int ch;
+
+	(void) setlocale(LC_ALL, "");
+#endif
+
+#ifdef SHELL
+	nextopt("");
+	argc -= argptr - argv;
+	argv = argptr;
+#else
+	while ((ch = getopt(argc, argv, "")) != -1)
+		switch (ch) {
+		case '?':
+		default:
+			usage();
+			return (1);
+		}
+	argc -= optind;
+	argv += optind;
+#endif
+
+	if (argc < 1) {
+		usage();
+		return (1);
+	}
+
+#ifdef SHELL
+	INTOFF;
+#endif
+	/*
+	 * Basic algorithm is to scan the format string for conversion
+	 * specifications -- once one is found, find out if the field
+	 * width or precision is a '*'; if it is, gather up value.  Note,
+	 * format strings are reused as necessary to use up the provided
+	 * arguments, arguments of zero/null string are provided to use
+	 * up the format string.
+	 */
+	fmt = format = *argv;
+	escape(fmt, 1, &len);		/* backslash interpretation */
+	rval = end = 0;
+	gargv = ++argv;
+
+	for (;;) {
+		maxargv = gargv;
+
+		myargv = gargv;
+		for (myargc = 0; gargv[myargc]; myargc++)
+			/* nop */;
+		start = fmt;
+		while (fmt < format + len) {
+			if (fmt[0] == '%') {
+				fwrite(start, 1, fmt - start, stdout);
+				if (fmt[1] == '%') {
+					/* %% prints a % */
+					putchar('%');
+					fmt += 2;
+				} else {
+					fmt = printf_doformat(fmt, &rval);
+					if (fmt == NULL || fmt == end_fmt) {
+#ifdef SHELL
+						INTON;
+#endif
+						return (fmt == NULL ? 1 : rval);
+					}
+					end = 0;
+				}
+				start = fmt;
+			} else
+				fmt++;
+			if (gargv > maxargv)
+				maxargv = gargv;
+		}
+		gargv = maxargv;
+
+		if (end == 1) {
+			warnx("missing format character");
+#ifdef SHELL
+			INTON;
+#endif
+			return (1);
+		}
+		fwrite(start, 1, fmt - start, stdout);
+		if (!*gargv) {
+#ifdef SHELL
+			INTON;
+#endif
+			return (rval);
+		}
+		/* Restart at the beginning of the format string. */
+		fmt = format;
+		end = 1;
+	}
+	/* NOTREACHED */
+}
+
+
+static char *
+printf_doformat(char *fmt, int *rval)
+{
+	static const char skip1[] = "#'-+ 0";
+	int fieldwidth, haveprec, havewidth, mod_ldbl, precision;
+	char convch, nextch;
+	char start[strlen(fmt) + 1];
+	char **fargv;
+	char *dptr;
+	int l;
+
+	dptr = start;
+	*dptr++ = '%';
+	*dptr = 0;
+
+	fmt++;
+
+	/* look for "n$" field index specifier */
+	l = strspn(fmt, digits);
+	if ((l > 0) && (fmt[l] == '$')) {
+		int idx = atoi(fmt);
+		if (idx <= myargc) {
+			gargv = &myargv[idx - 1];
+		} else {
+			gargv = &myargv[myargc];
+		}
+		if (gargv > maxargv)
+			maxargv = gargv;
+		fmt += l + 1;
+
+		/* save format argument */
+		fargv = gargv;
+	} else {
+		fargv = NULL;
+	}
+
+	/* skip to field width */
+	while (*fmt && strchr(skip1, *fmt) != NULL) {
+		*dptr++ = *fmt++;
+		*dptr = 0;
+	}
+
+	if (*fmt == '*') {
+
+		fmt++;
+		l = strspn(fmt, digits);
+		if ((l > 0) && (fmt[l] == '$')) {
+			int idx = atoi(fmt);
+			if (fargv == NULL) {
+				warnx("incomplete use of n$");
+				return (NULL);
+			}
+			if (idx <= myargc) {
+				gargv = &myargv[idx - 1];
+			} else {
+				gargv = &myargv[myargc];
+			}
+			fmt += l + 1;
+		} else if (fargv != NULL) {
+			warnx("incomplete use of n$");
+			return (NULL);
+		}
+
+		if (getint(&fieldwidth))
+			return (NULL);
+		if (gargv > maxargv)
+			maxargv = gargv;
+		havewidth = 1;
+
+		*dptr++ = '*';
+		*dptr = 0;
+	} else {
+		havewidth = 0;
+
+		/* skip to possible '.', get following precision */
+		while (isdigit(*fmt)) {
+			*dptr++ = *fmt++;
+			*dptr = 0;
+		}
+	}
+
+	if (*fmt == '.') {
+		/* precision present? */
+		fmt++;
+		*dptr++ = '.';
+
+		if (*fmt == '*') {
+
+			fmt++;
+			l = strspn(fmt, digits);
+			if ((l > 0) && (fmt[l] == '$')) {
+				int idx = atoi(fmt);
+				if (fargv == NULL) {
+					warnx("incomplete use of n$");
+					return (NULL);
+				}
+				if (idx <= myargc) {
+					gargv = &myargv[idx - 1];
+				} else {
+					gargv = &myargv[myargc];
+				}
+				fmt += l + 1;
+			} else if (fargv != NULL) {
+				warnx("incomplete use of n$");
+				return (NULL);
+			}
+
+			if (getint(&precision))
+				return (NULL);
+			if (gargv > maxargv)
+				maxargv = gargv;
+			haveprec = 1;
+			*dptr++ = '*';
+			*dptr = 0;
+		} else {
+			haveprec = 0;
+
+			/* skip to conversion char */
+			while (isdigit(*fmt)) {
+				*dptr++ = *fmt++;
+				*dptr = 0;
+			}
+		}
+	} else
+		haveprec = 0;
+	if (!*fmt) {
+		warnx("missing format character");
+		return (NULL);
+	}
+	*dptr++ = *fmt;
+	*dptr = 0;
+
+	/*
+	 * Look for a length modifier.  POSIX doesn't have these, so
+	 * we only support them for floating-point conversions, which
+	 * are extensions.  This is useful because the L modifier can
+	 * be used to gain extra range and precision, while omitting
+	 * it is more likely to produce consistent results on different
+	 * architectures.  This is not so important for integers
+	 * because overflow is the only bad thing that can happen to
+	 * them, but consider the command  printf %a 1.1
+	 */
+	if (*fmt == 'L') {
+		mod_ldbl = 1;
+		fmt++;
+		if (!strchr("aAeEfFgG", *fmt)) {
+			warnx("bad modifier L for %%%c", *fmt);
+			return (NULL);
+		}
+	} else {
+		mod_ldbl = 0;
+	}
+
+	/* save the current arg offset, and set to the format arg */
+	if (fargv != NULL) {
+		gargv = fargv;
+	}
+
+	convch = *fmt;
+	nextch = *++fmt;
+
+	*fmt = '\0';
+	switch (convch) {
+	case 'b': {
+		size_t len;
+		char *p;
+		int getout;
+
+		/* Convert "b" to "s" for output. */
+		start[strlen(start) - 1] = 's';
+		if ((p = strdup(getstr())) == NULL) {
+			warnx("%s", strerror(ENOMEM));
+			return (NULL);
+		}
+		getout = escape(p, 0, &len);
+		PF(start, p);
+		/* Restore format for next loop. */
+
+		free(p);
+		if (getout)
+			return (end_fmt);
+		break;
+	}
+	case 'c': {
+		char p;
+
+		p = getchr();
+		if (p != '\0')
+			PF(start, p);
+		break;
+	}
+	case 's': {
+		const char *p;
+
+		p = getstr();
+		PF(start, p);
+		break;
+	}
+	case 'd': case 'i': case 'o': case 'u': case 'x': case 'X': {
+		char *f;
+		intmax_t val;
+		uintmax_t uval;
+		int signedconv;
+
+		signedconv = (convch == 'd' || convch == 'i');
+		if ((f = mknum(start, convch)) == NULL)
+			return (NULL);
+		if (getnum(&val, &uval, signedconv))
+			*rval = 1;
+		if (signedconv)
+			PF(f, val);
+		else
+			PF(f, uval);
+		break;
+	}
+	case 'e': case 'E':
+	case 'f': case 'F':
+	case 'g': case 'G':
+	case 'a': case 'A': {
+		long double p;
+
+		if (getfloating(&p, mod_ldbl))
+			*rval = 1;
+		if (mod_ldbl)
+			PF(start, p);
+		else
+			PF(start, (double)p);
+		break;
+	}
+	default:
+		warnx("illegal format character %c", convch);
+		return (NULL);
+	}
+	*fmt = nextch;
+	/* return the gargv to the next element */
+	return (fmt);
+}
+
+static char *
+mknum(char *str, char ch)
+{
+	static char *copy;
+	static size_t copy_size;
+	char *newcopy;
+	size_t len, newlen;
+
+	len = strlen(str) + 2;
+	if (len > copy_size) {
+		newlen = ((len + 1023) >> 10) << 10;
+		if ((newcopy = realloc(copy, newlen)) == NULL) {
+			warnx("%s", strerror(ENOMEM));
+			return (NULL);
+		}
+		copy = newcopy;
+		copy_size = newlen;
+	}
+
+	memmove(copy, str, len - 3);
+	copy[len - 3] = 'j';
+	copy[len - 2] = ch;
+	copy[len - 1] = '\0';
+	return (copy);
+}
+
+static int
+escape(char *fmt, int percent, size_t *len)
+{
+	char *save, *store, c;
+	int value;
+
+	for (save = store = fmt; ((c = *fmt) != 0); ++fmt, ++store) {
+		if (c != '\\') {
+			*store = c;
+			continue;
+		}
+		switch (*++fmt) {
+		case '\0':		/* EOS, user error */
+			*store = '\\';
+			*++store = '\0';
+			*len = store - save;
+			return (0);
+		case '\\':		/* backslash */
+		case '\'':		/* single quote */
+			*store = *fmt;
+			break;
+		case 'a':		/* bell/alert */
+			*store = '\a';
+			break;
+		case 'b':		/* backspace */
+			*store = '\b';
+			break;
+		case 'c':
+			if (!percent) {
+				*store = '\0';
+				*len = store - save;
+				return (1);
+			}
+			*store = 'c';
+			break;
+		case 'f':		/* form-feed */
+			*store = '\f';
+			break;
+		case 'n':		/* newline */
+			*store = '\n';
+			break;
+		case 'r':		/* carriage-return */
+			*store = '\r';
+			break;
+		case 't':		/* horizontal tab */
+			*store = '\t';
+			break;
+		case 'v':		/* vertical tab */
+			*store = '\v';
+			break;
+					/* octal constant */
+		case '0': case '1': case '2': case '3':
+		case '4': case '5': case '6': case '7':
+			c = (!percent && *fmt == '0') ? 4 : 3;
+			for (value = 0;
+			    c-- && *fmt >= '0' && *fmt <= '7'; ++fmt) {
+				value <<= 3;
+				value += *fmt - '0';
+			}
+			--fmt;
+			if (percent && value == '%') {
+				*store++ = '%';
+				*store = '%';
+			} else
+				*store = (char)value;
+			break;
+		default:
+			*store = *fmt;
+			break;
+		}
+	}
+	*store = '\0';
+	*len = store - save;
+	return (0);
+}
+
+static int
+getchr(void)
+{
+	if (!*gargv)
+		return ('\0');
+	return ((int)**gargv++);
+}
+
+static const char *
+getstr(void)
+{
+	if (!*gargv)
+		return ("");
+	return (*gargv++);
+}
+
+static int
+getint(int *ip)
+{
+	intmax_t val;
+	uintmax_t uval;
+	int rval;
+
+	if (getnum(&val, &uval, 1))
+		return (1);
+	rval = 0;
+	if (val < INT_MIN || val > INT_MAX) {
+		warnx("%s: %s", *gargv, strerror(ERANGE));
+		rval = 1;
+	}
+	*ip = (int)val;
+	return (rval);
+}
+
+static int
+getnum(intmax_t *ip, uintmax_t *uip, int signedconv)
+{
+	char *ep;
+	int rval;
+
+	if (!*gargv) {
+		*ip = *uip = 0;
+		return (0);
+	}
+	if (**gargv == '"' || **gargv == '\'') {
+		if (signedconv)
+			*ip = asciicode();
+		else
+			*uip = asciicode();
+		return (0);
+	}
+	rval = 0;
+	errno = 0;
+	if (signedconv)
+		*ip = strtoimax(*gargv, &ep, 0);
+	else
+		*uip = strtoumax(*gargv, &ep, 0);
+	if (ep == *gargv) {
+		warnx("%s: expected numeric value", *gargv);
+		rval = 1;
+	}
+	else if (*ep != '\0') {
+		warnx("%s: not completely converted", *gargv);
+		rval = 1;
+	}
+	if (errno == ERANGE) {
+		warnx("%s: %s", *gargv, strerror(ERANGE));
+		rval = 1;
+	}
+	++gargv;
+	return (rval);
+}
+
+static int
+getfloating(long double *dp, int mod_ldbl)
+{
+	char *ep;
+	int rval;
+
+	if (!*gargv) {
+		*dp = 0.0;
+		return (0);
+	}
+	if (**gargv == '"' || **gargv == '\'') {
+		*dp = asciicode();
+		return (0);
+	}
+	rval = 0;
+	errno = 0;
+	if (mod_ldbl)
+		*dp = strtold(*gargv, &ep);
+	else
+		*dp = strtod(*gargv, &ep);
+	if (ep == *gargv) {
+		warnx("%s: expected numeric value", *gargv);
+		rval = 1;
+	} else if (*ep != '\0') {
+		warnx("%s: not completely converted", *gargv);
+		rval = 1;
+	}
+	if (errno == ERANGE) {
+		warnx("%s: %s", *gargv, strerror(ERANGE));
+		rval = 1;
+	}
+	++gargv;
+	return (rval);
+}
+
+static int
+asciicode(void)
+{
+	int ch;
+	wchar_t wch;
+	mbstate_t mbs;
+
+	ch = (unsigned char)**gargv;
+	if (ch == '\'' || ch == '"') {
+		memset(&mbs, 0, sizeof(mbs));
+		switch (mbrtowc(&wch, *gargv + 1, MB_LEN_MAX, &mbs)) {
+		case (size_t)-2:
+		case (size_t)-1:
+			wch = (unsigned char)gargv[0][1];
+			break;
+		case 0:
+			wch = 0;
+			break;
+		}
+		ch = wch;
+	}
+	++gargv;
+	return (ch);
+}
+
+static void
+usage(void)
+{
+	(void)fprintf(stderr, "usage: printf format [arguments ...]\n");
+}
diff --git a/bin/1sh/redir.c b/bin/1sh/redir.c
new file mode 100644
index 00000000..f8fd9324
--- /dev/null
+++ b/bin/1sh/redir.c
@@ -0,0 +1,365 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)redir.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/redir.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+/*
+ * Code for dealing with input/output redirection.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "expand.h"
+#include "redir.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "options.h"
+
+
+#define EMPTY -2		/* marks an unused slot in redirtab */
+#define CLOSED -1		/* fd was not open before redir */
+
+
+struct redirtab {
+	struct redirtab *next;
+	int renamed[10];
+	int fd0_redirected;
+	unsigned int empty_redirs;
+};
+
+
+static struct redirtab *redirlist;
+
+/*
+ * We keep track of whether or not fd0 has been redirected.  This is for
+ * background commands, where we want to redirect fd0 to /dev/null only
+ * if it hasn't already been redirected.
+*/
+static int fd0_redirected = 0;
+
+/* Number of redirtabs that have not been allocated. */
+static unsigned int empty_redirs = 0;
+
+static void openredirect(union node *, char[10 ]);
+static int openhere(union node *);
+
+
+/*
+ * Process a list of redirection commands.  If the REDIR_PUSH flag is set,
+ * old file descriptors are stashed away so that the redirection can be
+ * undone by calling popredir.  If the REDIR_BACKQ flag is set, then the
+ * standard output, and the standard error if it becomes a duplicate of
+ * stdout, is saved in memory.
+*
+ * We suppress interrupts so that we won't leave open file
+ * descriptors around.  Because the signal handler remains
+ * installed and we do not use system call restart, interrupts
+ * will still abort blocking opens such as fifos (they will fail
+ * with EINTR). There is, however, a race condition if an interrupt
+ * arrives after INTOFF and before open blocks.
+ */
+
+void
+redirect(union node *redir, int flags)
+{
+	union node *n;
+	struct redirtab *sv = NULL;
+	int i;
+	int fd;
+	char memory[10];	/* file descriptors to write to memory */
+
+	INTOFF;
+	for (i = 10 ; --i >= 0 ; )
+		memory[i] = 0;
+	memory[1] = flags & REDIR_BACKQ;
+	if (flags & REDIR_PUSH) {
+		empty_redirs++;
+		if (redir != NULL) {
+			sv = ckmalloc(sizeof (struct redirtab));
+			for (i = 0 ; i < 10 ; i++)
+				sv->renamed[i] = EMPTY;
+			sv->fd0_redirected = fd0_redirected;
+			sv->empty_redirs = empty_redirs - 1;
+			sv->next = redirlist;
+			redirlist = sv;
+			empty_redirs = 0;
+		}
+	}
+	for (n = redir ; n ; n = n->nfile.next) {
+		fd = n->nfile.fd;
+		if (fd == 0)
+			fd0_redirected = 1;
+		if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
+		    n->ndup.dupfd == fd)
+			continue; /* redirect from/to same file descriptor */
+
+		if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
+			INTOFF;
+			if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) {
+				switch (errno) {
+				case EBADF:
+					i = CLOSED;
+					break;
+				default:
+					INTON;
+					error("%d: %s", fd, strerror(errno));
+					break;
+				}
+			}
+			sv->renamed[fd] = i;
+			INTON;
+		}
+		openredirect(n, memory);
+		INTON;
+		INTOFF;
+	}
+	if (memory[1])
+		out1 = &memout;
+	if (memory[2])
+		out2 = &memout;
+	INTON;
+}
+
+
+static void
+openredirect(union node *redir, char memory[10])
+{
+	struct stat sb;
+	int fd = redir->nfile.fd;
+	const char *fname;
+	int f;
+	int e;
+
+	memory[fd] = 0;
+	switch (redir->nfile.type) {
+	case NFROM:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_RDONLY)) < 0)
+			error("cannot open %s: %s", fname, strerror(errno));
+		break;
+	case NFROMTO:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NTO:
+		if (Cflag) {
+			fname = redir->nfile.expfname;
+			if (stat(fname, &sb) == -1) {
+				if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0)
+					error("cannot create %s: %s", fname, strerror(errno));
+			} else if (!S_ISREG(sb.st_mode)) {
+				if ((f = open(fname, O_WRONLY, 0666)) < 0)
+					error("cannot create %s: %s", fname, strerror(errno));
+				if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
+					close(f);
+					error("cannot create %s: %s", fname,
+					    strerror(EEXIST));
+				}
+			} else
+				error("cannot create %s: %s", fname,
+				    strerror(EEXIST));
+			break;
+		}
+		/* FALLTHROUGH */
+	case NCLOBBER:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NAPPEND:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NTOFD:
+	case NFROMFD:
+		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
+			if (memory[redir->ndup.dupfd])
+				memory[fd] = 1;
+			else {
+				if (dup2(redir->ndup.dupfd, fd) < 0)
+					error("%d: %s", redir->ndup.dupfd,
+							strerror(errno));
+			}
+		} else {
+			close(fd);
+		}
+		return;
+	case NHERE:
+	case NXHERE:
+		f = openhere(redir);
+		break;
+	default:
+		abort();
+	}
+	if (f != fd) {
+		if (dup2(f, fd) == -1) {
+			e = errno;
+			close(f);
+			error("%d: %s", fd, strerror(e));
+		}
+		close(f);
+	}
+}
+
+
+/*
+ * Handle here documents.  Normally we fork off a process to write the
+ * data to a pipe.  If the document is short, we can stuff the data in
+ * the pipe without forking.
+ */
+
+static int
+openhere(union node *redir)
+{
+	const char *p;
+	int pip[2];
+	size_t len = 0;
+	int flags;
+	ssize_t written = 0;
+
+	if (pipe(pip) < 0)
+		error("Pipe call failed: %s", strerror(errno));
+
+	if (redir->type == NXHERE)
+		p = redir->nhere.expdoc;
+	else
+		p = redir->nhere.doc->narg.text;
+	len = strlen(p);
+	if (len == 0)
+		goto out;
+	flags = fcntl(pip[1], F_GETFL, 0);
+	if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) {
+		written = write(pip[1], p, len);
+		if (written < 0)
+			written = 0;
+		if ((size_t)written == len)
+			goto out;
+		fcntl(pip[1], F_SETFL, flags);
+	}
+
+	if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
+		close(pip[0]);
+		signal(SIGINT, SIG_IGN);
+		signal(SIGQUIT, SIG_IGN);
+		signal(SIGHUP, SIG_IGN);
+		signal(SIGTSTP, SIG_IGN);
+		signal(SIGPIPE, SIG_DFL);
+		xwrite(pip[1], p + written, len - written);
+		_exit(0);
+	}
+out:
+	close(pip[1]);
+	return pip[0];
+}
+
+
+
+/*
+ * Undo the effects of the last redirection.
+ */
+
+void
+popredir(void)
+{
+	struct redirtab *rp = redirlist;
+	int i;
+
+	INTOFF;
+	if (empty_redirs > 0) {
+		empty_redirs--;
+		INTON;
+		return;
+	}
+	for (i = 0 ; i < 10 ; i++) {
+		if (rp->renamed[i] != EMPTY) {
+			if (rp->renamed[i] >= 0) {
+				dup2(rp->renamed[i], i);
+				close(rp->renamed[i]);
+			} else {
+				close(i);
+			}
+		}
+	}
+	fd0_redirected = rp->fd0_redirected;
+	empty_redirs = rp->empty_redirs;
+	redirlist = rp->next;
+	ckfree(rp);
+	INTON;
+}
+
+/* Return true if fd 0 has already been redirected at least once.  */
+int
+fd0_redirected_p(void)
+{
+        return fd0_redirected != 0;
+}
+
+/*
+ * Discard all saved file descriptors.
+ */
+
+void
+clearredir(void)
+{
+	struct redirtab *rp;
+	int i;
+
+	for (rp = redirlist ; rp ; rp = rp->next) {
+		for (i = 0 ; i < 10 ; i++) {
+			if (rp->renamed[i] >= 0) {
+				close(rp->renamed[i]);
+			}
+			rp->renamed[i] = EMPTY;
+		}
+	}
+}
diff --git a/bin/1sh/redir.h b/bin/1sh/redir.h
new file mode 100644
index 00000000..6946f6a7
--- /dev/null
+++ b/bin/1sh/redir.h
@@ -0,0 +1,47 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)redir.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/redir.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+/* flags passed to redirect */
+#define REDIR_PUSH 01		/* save previous values of file descriptors */
+#define REDIR_BACKQ 02		/* save the command output in memory */
+
+union node;
+void redirect(union node *, int);
+void popredir(void);
+int fd0_redirected_p(void);
+void clearredir(void);
+
diff --git a/bin/1sh/shell.h b/bin/1sh/shell.h
new file mode 100644
index 00000000..98ac98df
--- /dev/null
+++ b/bin/1sh/shell.h
@@ -0,0 +1,77 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)shell.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/shell.h 345117 2019-03-13 21:53:10Z jilles $
+ */
+
+#ifndef SHELL_H_
+#define SHELL_H_
+
+#include <inttypes.h>
+
+/*
+ * The follow should be set to reflect the type of system you have:
+ *	JOBS -> 1 if you have Berkeley job control, 0 otherwise.
+ *	define DEBUG=1 to compile in debugging (set global "debug" to turn on)
+ *	define DEBUG=2 to compile in and turn on debugging.
+ *
+ * When debugging is on, debugging info will be written to ./trace and
+ * a quit signal will generate a core dump.
+ */
+
+
+#define	JOBS 1
+/* #define DEBUG 1 */
+
+/*
+ * Type of used arithmetics. SUSv3 requires us to have at least signed long.
+ */
+typedef intmax_t arith_t;
+#define	ARITH_FORMAT_STR  "%" PRIdMAX
+#define	ARITH_MIN INTMAX_MIN
+#define	ARITH_MAX INTMAX_MAX
+
+typedef void *pointer;
+
+#include <sys/cdefs.h>
+
+extern char nullstr[1];		/* null string */
+
+#ifdef DEBUG
+#define TRACE(param)  sh_trace param
+#else
+#define TRACE(param)
+#endif
+
+#endif /* !SHELL_H_ */
diff --git a/bin/1sh/show.c b/bin/1sh/show.c
new file mode 100644
index 00000000..a87a506d
--- /dev/null
+++ b/bin/1sh/show.c
@@ -0,0 +1,410 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)show.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/show.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include "shell.h"
+#include "parser.h"
+#include "nodes.h"
+#include "mystring.h"
+#include "show.h"
+
+
+#ifdef DEBUG
+static void shtree(union node *, int, char *, FILE*);
+static void shcmd(union node *, FILE *);
+static void sharg(union node *, FILE *);
+static void indent(int, char *, FILE *);
+static void trstring(char *);
+
+
+void
+showtree(union node *n)
+{
+	trputs("showtree called\n");
+	shtree(n, 1, NULL, stdout);
+}
+
+
+static void
+shtree(union node *n, int ind, char *pfx, FILE *fp)
+{
+	struct nodelist *lp;
+	char *s;
+
+	if (n == NULL)
+		return;
+
+	indent(ind, pfx, fp);
+	switch(n->type) {
+	case NSEMI:
+		s = "; ";
+		goto binop;
+	case NAND:
+		s = " && ";
+		goto binop;
+	case NOR:
+		s = " || ";
+binop:
+		shtree(n->nbinary.ch1, ind, NULL, fp);
+	   /*    if (ind < 0) */
+			fputs(s, fp);
+		shtree(n->nbinary.ch2, ind, NULL, fp);
+		break;
+	case NCMD:
+		shcmd(n, fp);
+		if (ind >= 0)
+			putc('\n', fp);
+		break;
+	case NPIPE:
+		for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
+			shcmd(lp->n, fp);
+			if (lp->next)
+				fputs(" | ", fp);
+		}
+		if (n->npipe.backgnd)
+			fputs(" &", fp);
+		if (ind >= 0)
+			putc('\n', fp);
+		break;
+	default:
+		fprintf(fp, "<node type %d>", n->type);
+		if (ind >= 0)
+			putc('\n', fp);
+		break;
+	}
+}
+
+
+
+static void
+shcmd(union node *cmd, FILE *fp)
+{
+	union node *np;
+	int first;
+	char *s;
+	int dftfd;
+
+	first = 1;
+	for (np = cmd->ncmd.args ; np ; np = np->narg.next) {
+		if (! first)
+			putchar(' ');
+		sharg(np, fp);
+		first = 0;
+	}
+	for (np = cmd->ncmd.redirect ; np ; np = np->nfile.next) {
+		if (! first)
+			putchar(' ');
+		switch (np->nfile.type) {
+			case NTO:	s = ">";  dftfd = 1; break;
+			case NAPPEND:	s = ">>"; dftfd = 1; break;
+			case NTOFD:	s = ">&"; dftfd = 1; break;
+			case NCLOBBER:	s = ">|"; dftfd = 1; break;
+			case NFROM:	s = "<";  dftfd = 0; break;
+			case NFROMTO:	s = "<>"; dftfd = 0; break;
+			case NFROMFD:	s = "<&"; dftfd = 0; break;
+			case NHERE:	s = "<<"; dftfd = 0; break;
+			case NXHERE:	s = "<<"; dftfd = 0; break;
+			default:  	s = "*error*"; dftfd = 0; break;
+		}
+		if (np->nfile.fd != dftfd)
+			fprintf(fp, "%d", np->nfile.fd);
+		fputs(s, fp);
+		if (np->nfile.type == NTOFD || np->nfile.type == NFROMFD) {
+			if (np->ndup.dupfd >= 0)
+				fprintf(fp, "%d", np->ndup.dupfd);
+			else
+				fprintf(fp, "-");
+		} else if (np->nfile.type == NHERE) {
+				fprintf(fp, "HERE");
+		} else if (np->nfile.type == NXHERE) {
+				fprintf(fp, "XHERE");
+		} else {
+			sharg(np->nfile.fname, fp);
+		}
+		first = 0;
+	}
+}
+
+
+
+static void
+sharg(union node *arg, FILE *fp)
+{
+	char *p;
+	struct nodelist *bqlist;
+	int subtype;
+
+	if (arg->type != NARG) {
+		printf("<node type %d>\n", arg->type);
+		fflush(stdout);
+		abort();
+	}
+	bqlist = arg->narg.backquote;
+	for (p = arg->narg.text ; *p ; p++) {
+		switch (*p) {
+		case CTLESC:
+			putc(*++p, fp);
+			break;
+		case CTLVAR:
+			putc('$', fp);
+			putc('{', fp);
+			subtype = *++p;
+			if (subtype == VSLENGTH)
+				putc('#', fp);
+
+			while (*p != '=')
+				putc(*p++, fp);
+
+			if (subtype & VSNUL)
+				putc(':', fp);
+
+			switch (subtype & VSTYPE) {
+			case VSNORMAL:
+				putc('}', fp);
+				break;
+			case VSMINUS:
+				putc('-', fp);
+				break;
+			case VSPLUS:
+				putc('+', fp);
+				break;
+			case VSQUESTION:
+				putc('?', fp);
+				break;
+			case VSASSIGN:
+				putc('=', fp);
+				break;
+			case VSTRIMLEFT:
+				putc('#', fp);
+				break;
+			case VSTRIMLEFTMAX:
+				putc('#', fp);
+				putc('#', fp);
+				break;
+			case VSTRIMRIGHT:
+				putc('%', fp);
+				break;
+			case VSTRIMRIGHTMAX:
+				putc('%', fp);
+				putc('%', fp);
+				break;
+			case VSLENGTH:
+				break;
+			default:
+				printf("<subtype %d>", subtype);
+			}
+			break;
+		case CTLENDVAR:
+		     putc('}', fp);
+		     break;
+		case CTLBACKQ:
+		case CTLBACKQ|CTLQUOTE:
+			putc('$', fp);
+			putc('(', fp);
+			shtree(bqlist->n, -1, NULL, fp);
+			putc(')', fp);
+			break;
+		default:
+			putc(*p, fp);
+			break;
+		}
+	}
+}
+
+
+static void
+indent(int amount, char *pfx, FILE *fp)
+{
+	int i;
+
+	for (i = 0 ; i < amount ; i++) {
+		if (pfx && i == amount - 1)
+			fputs(pfx, fp);
+		putc('\t', fp);
+	}
+}
+
+
+/*
+ * Debugging stuff.
+ */
+
+
+FILE *tracefile;
+
+#if DEBUG >= 2
+int debug = 1;
+#else
+int debug = 0;
+#endif
+
+
+void
+trputc(int c)
+{
+	if (tracefile == NULL)
+		return;
+	putc(c, tracefile);
+	if (c == '\n')
+		fflush(tracefile);
+}
+
+
+void
+sh_trace(const char *fmt, ...)
+{
+	va_list va;
+	va_start(va, fmt);
+	if (tracefile != NULL) {
+		(void) vfprintf(tracefile, fmt, va);
+		if (strchr(fmt, '\n'))
+			(void) fflush(tracefile);
+	}
+	va_end(va);
+}
+
+
+void
+trputs(const char *s)
+{
+	if (tracefile == NULL)
+		return;
+	fputs(s, tracefile);
+	if (strchr(s, '\n'))
+		fflush(tracefile);
+}
+
+
+static void
+trstring(char *s)
+{
+	char *p;
+	char c;
+
+	if (tracefile == NULL)
+		return;
+	putc('"', tracefile);
+	for (p = s ; *p ; p++) {
+		switch (*p) {
+		case '\n':  c = 'n';  goto backslash;
+		case '\t':  c = 't';  goto backslash;
+		case '\r':  c = 'r';  goto backslash;
+		case '"':  c = '"';  goto backslash;
+		case '\\':  c = '\\';  goto backslash;
+		case CTLESC:  c = 'e';  goto backslash;
+		case CTLVAR:  c = 'v';  goto backslash;
+		case CTLVAR+CTLQUOTE:  c = 'V';  goto backslash;
+		case CTLBACKQ:  c = 'q';  goto backslash;
+		case CTLBACKQ+CTLQUOTE:  c = 'Q';  goto backslash;
+backslash:	  putc('\\', tracefile);
+			putc(c, tracefile);
+			break;
+		default:
+			if (*p >= ' ' && *p <= '~')
+				putc(*p, tracefile);
+			else {
+				putc('\\', tracefile);
+				putc(*p >> 6 & 03, tracefile);
+				putc(*p >> 3 & 07, tracefile);
+				putc(*p & 07, tracefile);
+			}
+			break;
+		}
+	}
+	putc('"', tracefile);
+}
+
+
+void
+trargs(char **ap)
+{
+	if (tracefile == NULL)
+		return;
+	while (*ap) {
+		trstring(*ap++);
+		if (*ap)
+			putc(' ', tracefile);
+		else
+			putc('\n', tracefile);
+	}
+	fflush(tracefile);
+}
+
+
+void
+opentrace(void)
+{
+	char s[100];
+	int flags;
+
+	if (!debug)
+		return;
+#ifdef not_this_way
+	{
+		char *p;
+		if ((p = getenv("HOME")) == NULL) {
+			if (geteuid() == 0)
+				p = "/";
+			else
+				p = "/tmp";
+		}
+		strcpy(s, p);
+		strcat(s, "/trace");
+	}
+#else
+	strcpy(s, "./trace");
+#endif /* not_this_way */
+	if ((tracefile = fopen(s, "a")) == NULL) {
+		fprintf(stderr, "Can't open %s: %s\n", s, strerror(errno));
+		return;
+	}
+	if ((flags = fcntl(fileno(tracefile), F_GETFL, 0)) >= 0)
+		fcntl(fileno(tracefile), F_SETFL, flags | O_APPEND);
+	fputs("\nTracing started.\n", tracefile);
+	fflush(tracefile);
+}
+#endif /* DEBUG */
diff --git a/bin/1sh/show.h b/bin/1sh/show.h
new file mode 100644
index 00000000..68840549
--- /dev/null
+++ b/bin/1sh/show.h
@@ -0,0 +1,42 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1995
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)show.h	1.1 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/show.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+void showtree(union node *);
+#ifdef DEBUG
+void sh_trace(const char *, ...) __attribute__((format(printf, 1, 2)));
+void trargs(char **);
+void trputc(int);
+void trputs(const char *);
+void opentrace(void);
+#endif
diff --git a/bin/1sh/test.c b/bin/1sh/test.c
new file mode 100644
index 00000000..54c16eef
--- /dev/null
+++ b/bin/1sh/test.c
@@ -0,0 +1,630 @@
+/*	$NetBSD: test.c,v 1.21 1999/04/05 09:48:38 kleink Exp $	*/
+
+/*-
+ * test(1); version 7-like  --  author Erik Baalbergen
+ * modified by Eric Gisin to be used as built-in.
+ * modified by Arnold Robbins to add SVR3 compatibility
+ * (-x -c -b -p -u -g -k) plus Korn's -L -nt -ot -ef and new -S (socket).
+ * modified by J.T. Conklin for NetBSD.
+ *
+ * This program is in the Public Domain.
+ */
+/*
+ * Important: This file is used both as a standalone program /bin/test and
+ * as a builtin for /bin/sh (#define SHELL).
+ */
+
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/test/test.c 298232 2016-04-19 00:38:07Z araujo $ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef SHELL
+#define main testcmd
+#include "bltin.h"
+#else
+#include <locale.h>
+
+static void error(const char *, ...) __attribute__((noreturn)) __attribute__((format(printf, 1, 2)));
+
+static void
+error(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	verrx(2, msg, ap);
+	/*NOTREACHED*/
+	va_end(ap);
+}
+#endif
+
+/* test(1) accepts the following grammar:
+	oexpr	::= aexpr | aexpr "-o" oexpr ;
+	aexpr	::= nexpr | nexpr "-a" aexpr ;
+	nexpr	::= primary | "!" primary
+	primary	::= unary-operator operand
+		| operand binary-operator operand
+		| operand
+		| "(" oexpr ")"
+		;
+	unary-operator ::= "-r"|"-w"|"-x"|"-f"|"-d"|"-c"|"-b"|"-p"|
+		"-u"|"-g"|"-k"|"-s"|"-t"|"-z"|"-n"|"-o"|"-O"|"-G"|"-L"|"-S";
+
+	binary-operator ::= "="|"!="|"-eq"|"-ne"|"-ge"|"-gt"|"-le"|"-lt"|
+			"-nt"|"-ot"|"-ef";
+	operand ::= <any legal UNIX file name>
+*/
+
+enum token_types {
+	UNOP = 0x100,
+	BINOP = 0x200,
+	BUNOP = 0x300,
+	BBINOP = 0x400,
+	PAREN = 0x500
+};
+
+enum token {
+	EOI,
+	OPERAND,
+	FILRD = UNOP + 1,
+	FILWR,
+	FILEX,
+	FILEXIST,
+	FILREG,
+	FILDIR,
+	FILCDEV,
+	FILBDEV,
+	FILFIFO,
+	FILSOCK,
+	FILSYM,
+	FILGZ,
+	FILTT,
+	FILSUID,
+	FILSGID,
+	FILSTCK,
+	STREZ,
+	STRNZ,
+	FILUID,
+	FILGID,
+	FILNT = BINOP + 1,
+	FILOT,
+	FILEQ,
+	STREQ,
+	STRNE,
+	STRLT,
+	STRGT,
+	INTEQ,
+	INTNE,
+	INTGE,
+	INTGT,
+	INTLE,
+	INTLT,
+	UNOT = BUNOP + 1,
+	BAND = BBINOP + 1,
+	BOR,
+	LPAREN = PAREN + 1,
+	RPAREN
+};
+
+#define TOKEN_TYPE(token) ((token) & 0xff00)
+
+static const struct t_op {
+	char op_text[2];
+	short op_num;
+} ops1[] = {
+	{"=",	STREQ},
+	{"<",	STRLT},
+	{">",	STRGT},
+	{"!",	UNOT},
+	{"(",	LPAREN},
+	{")",	RPAREN},
+}, opsm1[] = {
+	{"r",	FILRD},
+	{"w",	FILWR},
+	{"x",	FILEX},
+	{"e",	FILEXIST},
+	{"f",	FILREG},
+	{"d",	FILDIR},
+	{"c",	FILCDEV},
+	{"b",	FILBDEV},
+	{"p",	FILFIFO},
+	{"u",	FILSUID},
+	{"g",	FILSGID},
+	{"k",	FILSTCK},
+	{"s",	FILGZ},
+	{"t",	FILTT},
+	{"z",	STREZ},
+	{"n",	STRNZ},
+	{"h",	FILSYM},		/* for backwards compat */
+	{"O",	FILUID},
+	{"G",	FILGID},
+	{"L",	FILSYM},
+	{"S",	FILSOCK},
+	{"a",	BAND},
+	{"o",	BOR},
+}, ops2[] = {
+	{"==",	STREQ},
+	{"!=",	STRNE},
+}, opsm2[] = {
+	{"eq",	INTEQ},
+	{"ne",	INTNE},
+	{"ge",	INTGE},
+	{"gt",	INTGT},
+	{"le",	INTLE},
+	{"lt",	INTLT},
+	{"nt",	FILNT},
+	{"ot",	FILOT},
+	{"ef",	FILEQ},
+};
+
+static int nargc;
+static char **t_wp;
+static int parenlevel;
+
+static int	aexpr(enum token);
+static int	binop(enum token);
+static int	equalf(const char *, const char *);
+static int	filstat(char *, enum token);
+static int	getn(const char *);
+static intmax_t	getq(const char *);
+static int	intcmp(const char *, const char *);
+static int	isunopoperand(void);
+static int	islparenoperand(void);
+static int	isrparenoperand(void);
+static int	newerf(const char *, const char *);
+static int	nexpr(enum token);
+static int	oexpr(enum token);
+static int	olderf(const char *, const char *);
+static int	primary(enum token);
+static void	syntax(const char *, const char *);
+static enum	token t_lex(char *);
+
+int
+main(int argc, char **argv)
+{
+	int	res;
+	char	*p;
+
+	if ((p = strrchr(argv[0], '/')) == NULL)
+		p = argv[0];
+	else
+		p++;
+	if (strcmp(p, "[") == 0) {
+		if (strcmp(argv[--argc], "]") != 0)
+			error("missing ]");
+		argv[argc] = NULL;
+	}
+
+	/* no expression => false */
+	if (--argc <= 0)
+		return 1;
+
+#ifndef SHELL
+	(void)setlocale(LC_CTYPE, "");
+#endif
+	nargc = argc;
+	t_wp = &argv[1];
+	parenlevel = 0;
+	if (nargc == 4 && strcmp(*t_wp, "!") == 0) {
+		/* Things like ! "" -o x do not fit in the normal grammar. */
+		--nargc;
+		++t_wp;
+		res = oexpr(t_lex(*t_wp));
+	} else
+		res = !oexpr(t_lex(*t_wp));
+
+	if (--nargc > 0)
+		syntax(*t_wp, "unexpected operator");
+
+	return res;
+}
+
+static void
+syntax(const char *op, const char *msg)
+{
+
+	if (op && *op)
+		error("%s: %s", op, msg);
+	else
+		error("%s", msg);
+}
+
+static int
+oexpr(enum token n)
+{
+	int res;
+
+	res = aexpr(n);
+	if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) == BOR)
+		return oexpr(t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) ||
+		    res;
+	t_wp--;
+	nargc++;
+	return res;
+}
+
+static int
+aexpr(enum token n)
+{
+	int res;
+
+	res = nexpr(n);
+	if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) == BAND)
+		return aexpr(t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) &&
+		    res;
+	t_wp--;
+	nargc++;
+	return res;
+}
+
+static int
+nexpr(enum token n)
+{
+	if (n == UNOT)
+		return !nexpr(t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL));
+	return primary(n);
+}
+
+static int
+primary(enum token n)
+{
+	enum token nn;
+	int res;
+
+	if (n == EOI)
+		return 0;		/* missing expression */
+	if (n == LPAREN) {
+		parenlevel++;
+		if ((nn = t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) ==
+		    RPAREN) {
+			parenlevel--;
+			return 0;	/* missing expression */
+		}
+		res = oexpr(nn);
+		if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) != RPAREN)
+			syntax(NULL, "closing paren expected");
+		parenlevel--;
+		return res;
+	}
+	if (TOKEN_TYPE(n) == UNOP) {
+		/* unary expression */
+		if (--nargc == 0)
+			syntax(NULL, "argument expected"); /* impossible */
+		switch (n) {
+		case STREZ:
+			return strlen(*++t_wp) == 0;
+		case STRNZ:
+			return strlen(*++t_wp) != 0;
+		case FILTT:
+			return isatty(getn(*++t_wp));
+		default:
+			return filstat(*++t_wp, n);
+		}
+	}
+
+	nn = t_lex(nargc > 0 ? t_wp[1] : NULL);
+	if (TOKEN_TYPE(nn) == BINOP)
+		return binop(nn);
+
+	return strlen(*t_wp) > 0;
+}
+
+static int
+binop(enum token n)
+{
+	const char *opnd1, *op, *opnd2;
+
+	opnd1 = *t_wp;
+	op = nargc > 0 ? (--nargc, *++t_wp) : NULL;
+
+	if ((opnd2 = nargc > 0 ? (--nargc, *++t_wp) : NULL) == NULL)
+		syntax(op, "argument expected");
+
+	switch (n) {
+	case STREQ:
+		return strcmp(opnd1, opnd2) == 0;
+	case STRNE:
+		return strcmp(opnd1, opnd2) != 0;
+	case STRLT:
+		return strcmp(opnd1, opnd2) < 0;
+	case STRGT:
+		return strcmp(opnd1, opnd2) > 0;
+	case INTEQ:
+		return intcmp(opnd1, opnd2) == 0;
+	case INTNE:
+		return intcmp(opnd1, opnd2) != 0;
+	case INTGE:
+		return intcmp(opnd1, opnd2) >= 0;
+	case INTGT:
+		return intcmp(opnd1, opnd2) > 0;
+	case INTLE:
+		return intcmp(opnd1, opnd2) <= 0;
+	case INTLT:
+		return intcmp(opnd1, opnd2) < 0;
+	case FILNT:
+		return newerf (opnd1, opnd2);
+	case FILOT:
+		return olderf (opnd1, opnd2);
+	case FILEQ:
+		return equalf (opnd1, opnd2);
+	default:
+		abort();
+		/* NOTREACHED */
+	}
+}
+
+static int
+filstat(char *nm, enum token mode)
+{
+	struct stat s;
+
+	if (mode == FILSYM ? lstat(nm, &s) : stat(nm, &s))
+		return 0;
+
+	switch (mode) {
+	case FILRD:
+		return (faccessat(AT_FDCWD, nm, R_OK, AT_EACCESS) == 0);
+	case FILWR:
+		return (faccessat(AT_FDCWD, nm, W_OK, AT_EACCESS) == 0);
+	case FILEX:
+		/* XXX work around eaccess(2) false positives for superuser */
+		if (faccessat(AT_FDCWD, nm, X_OK, AT_EACCESS) != 0)
+			return 0;
+		if (S_ISDIR(s.st_mode) || geteuid() != 0)
+			return 1;
+		return (s.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0;
+	case FILEXIST:
+		return (faccessat(AT_FDCWD, nm, F_OK, AT_EACCESS) == 0);
+	case FILREG:
+		return S_ISREG(s.st_mode);
+	case FILDIR:
+		return S_ISDIR(s.st_mode);
+	case FILCDEV:
+		return S_ISCHR(s.st_mode);
+	case FILBDEV:
+		return S_ISBLK(s.st_mode);
+	case FILFIFO:
+		return S_ISFIFO(s.st_mode);
+	case FILSOCK:
+		return S_ISSOCK(s.st_mode);
+	case FILSYM:
+		return S_ISLNK(s.st_mode);
+	case FILSUID:
+		return (s.st_mode & S_ISUID) != 0;
+	case FILSGID:
+		return (s.st_mode & S_ISGID) != 0;
+	case FILSTCK:
+		return (s.st_mode & S_ISVTX) != 0;
+	case FILGZ:
+		return s.st_size > (off_t)0;
+	case FILUID:
+		return s.st_uid == geteuid();
+	case FILGID:
+		return s.st_gid == getegid();
+	default:
+		return 1;
+	}
+}
+
+static int
+find_op_1char(const struct t_op *op, const struct t_op *end, const char *s)
+{
+	char c;
+
+	c = s[0];
+	while (op != end) {
+		if (c == *op->op_text)
+			return op->op_num;
+		op++;
+	}
+	return OPERAND;
+}
+
+static int
+find_op_2char(const struct t_op *op, const struct t_op *end, const char *s)
+{
+	while (op != end) {
+		if (s[0] == op->op_text[0] && s[1] == op->op_text[1])
+			return op->op_num;
+		op++;
+	}
+	return OPERAND;
+}
+
+static int
+find_op(const char *s)
+{
+	if (s[0] == '\0')
+		return OPERAND;
+	else if (s[1] == '\0')
+		return find_op_1char(ops1, (&ops1)[1], s);
+	else if (s[2] == '\0')
+		return s[0] == '-' ? find_op_1char(opsm1, (&opsm1)[1], s + 1) :
+		    find_op_2char(ops2, (&ops2)[1], s);
+	else if (s[3] == '\0')
+		return s[0] == '-' ? find_op_2char(opsm2, (&opsm2)[1], s + 1) :
+		    OPERAND;
+	else
+		return OPERAND;
+}
+
+static enum token
+t_lex(char *s)
+{
+	int num;
+
+	if (s == NULL) {
+		return EOI;
+	}
+	num = find_op(s);
+	if (((TOKEN_TYPE(num) == UNOP || TOKEN_TYPE(num) == BUNOP)
+				&& isunopoperand()) ||
+	    (num == LPAREN && islparenoperand()) ||
+	    (num == RPAREN && isrparenoperand()))
+		return OPERAND;
+	return num;
+}
+
+static int
+isunopoperand(void)
+{
+	char *s;
+	char *t;
+	int num;
+
+	if (nargc == 1)
+		return 1;
+	s = *(t_wp + 1);
+	if (nargc == 2)
+		return parenlevel == 1 && strcmp(s, ")") == 0;
+	t = *(t_wp + 2);
+	num = find_op(s);
+	return TOKEN_TYPE(num) == BINOP &&
+	    (parenlevel == 0 || t[0] != ')' || t[1] != '\0');
+}
+
+static int
+islparenoperand(void)
+{
+	char *s;
+	int num;
+
+	if (nargc == 1)
+		return 1;
+	s = *(t_wp + 1);
+	if (nargc == 2)
+		return parenlevel == 1 && strcmp(s, ")") == 0;
+	if (nargc != 3)
+		return 0;
+	num = find_op(s);
+	return TOKEN_TYPE(num) == BINOP;
+}
+
+static int
+isrparenoperand(void)
+{
+	char *s;
+
+	if (nargc == 1)
+		return 0;
+	s = *(t_wp + 1);
+	if (nargc == 2)
+		return parenlevel == 1 && strcmp(s, ")") == 0;
+	return 0;
+}
+
+/* atoi with error detection */
+static int
+getn(const char *s)
+{
+	char *p;
+	long r;
+
+	errno = 0;
+	r = strtol(s, &p, 10);
+
+	if (s == p)
+		error("%s: bad number", s);
+
+	if (errno != 0)
+		error((errno == EINVAL) ? "%s: bad number" :
+					  "%s: out of range", s);
+
+	while (isspace((unsigned char)*p))
+		p++;
+
+	if (*p)
+		error("%s: bad number", s);
+
+	return (int) r;
+}
+
+/* atoi with error detection and 64 bit range */
+static intmax_t
+getq(const char *s)
+{
+	char *p;
+	intmax_t r;
+
+	errno = 0;
+	r = strtoimax(s, &p, 10);
+
+	if (s == p)
+		error("%s: bad number", s);
+
+	if (errno != 0)
+		error((errno == EINVAL) ? "%s: bad number" :
+					  "%s: out of range", s);
+
+	while (isspace((unsigned char)*p))
+		p++;
+
+	if (*p)
+		error("%s: bad number", s);
+
+	return r;
+}
+
+static int
+intcmp (const char *s1, const char *s2)
+{
+	intmax_t q1, q2;
+
+
+	q1 = getq(s1);
+	q2 = getq(s2);
+
+	if (q1 > q2)
+		return 1;
+
+	if (q1 < q2)
+		return -1;
+
+	return 0;
+}
+
+static int
+newerf (const char *f1, const char *f2)
+{
+	struct stat b1, b2;
+
+	if (stat(f1, &b1) != 0 || stat(f2, &b2) != 0)
+		return 0;
+
+	if (b1.st_mtimespec.tv_sec > b2.st_mtimespec.tv_sec)
+		return 1;
+	if (b1.st_mtimespec.tv_sec < b2.st_mtimespec.tv_sec)
+		return 0;
+
+       return (b1.st_mtimespec.tv_nsec > b2.st_mtimespec.tv_nsec);
+}
+
+static int
+olderf (const char *f1, const char *f2)
+{
+	return (newerf(f2, f1));
+}
+
+static int
+equalf (const char *f1, const char *f2)
+{
+	struct stat b1, b2;
+
+	return (stat (f1, &b1) == 0 &&
+		stat (f2, &b2) == 0 &&
+		b1.st_dev == b2.st_dev &&
+		b1.st_ino == b2.st_ino);
+}
diff --git a/bin/1sh/trap.c b/bin/1sh/trap.c
new file mode 100644
index 00000000..fed13fcf
--- /dev/null
+++ b/bin/1sh/trap.c
@@ -0,0 +1,553 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)trap.c	8.5 (Berkeley) 6/5/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/trap.c 326025 2017-11-20 19:49:47Z pfg $ */
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"
+#include "jobs.h"
+#include "show.h"
+#include "options.h"
+#include "syntax.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "trap.h"
+#include "mystring.h"
+#include "builtins.h"
+#include "myhistedit.h"
+
+
+/*
+ * Sigmode records the current value of the signal handlers for the various
+ * modes.  A value of zero means that the current handler is not known.
+ * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
+ */
+
+#define S_DFL 1			/* default signal handling (SIG_DFL) */
+#define S_CATCH 2		/* signal is caught */
+#define S_IGN 3			/* signal is ignored (SIG_IGN) */
+#define S_HARD_IGN 4		/* signal is ignored permanently */
+#define S_RESET 5		/* temporary - to reset a hard ignored sig */
+
+
+static char sigmode[NSIG];	/* current value of signal */
+volatile sig_atomic_t pendingsig;	/* indicates some signal received */
+volatile sig_atomic_t pendingsig_waitcmd;	/* indicates wait builtin should be interrupted */
+static int in_dotrap;			/* do we execute in a trap handler? */
+static char *volatile trap[NSIG];	/* trap handler commands */
+static volatile sig_atomic_t gotsig[NSIG];
+				/* indicates specified signal received */
+static int ignore_sigchld;	/* Used while handling SIGCHLD traps. */
+static int last_trapsig;
+
+static int exiting;		/* exitshell() has been called */
+static int exiting_exitstatus;	/* value passed to exitshell() */
+
+static int getsigaction(int, sig_t *);
+
+
+/*
+ * Map a string to a signal number.
+ *
+ * Note: the signal number may exceed NSIG.
+ */
+static int
+sigstring_to_signum(char *sig)
+{
+
+	if (is_number(sig)) {
+		int signo;
+
+		signo = atoi(sig);
+		return ((signo >= 0 && signo < NSIG) ? signo : (-1));
+	} else if (strcasecmp(sig, "EXIT") == 0) {
+		return (0);
+	} else {
+		int n;
+
+		if (strncasecmp(sig, "SIG", 3) == 0)
+			sig += 3;
+		for (n = 1; n < NSIG; n++)
+			if (sys_signame[n] &&
+			    strcasecmp(sys_signame[n], sig) == 0)
+				return (n);
+	}
+	return (-1);
+}
+
+
+/*
+ * Print a list of valid signal names.
+ */
+static void
+printsignals(void)
+{
+	int n, outlen;
+
+	outlen = 0;
+	for (n = 1; n < NSIG; n++) {
+		if (sys_signame[n]) {
+			out1fmt("%s", sys_signame[n]);
+			outlen += strlen(sys_signame[n]);
+		} else {
+			out1fmt("%d", n);
+			outlen += 3;	/* good enough */
+		}
+		++outlen;
+		if (outlen > 71 || n == NSIG - 1) {
+			out1str("\n");
+			outlen = 0;
+		} else {
+			out1c(' ');
+		}
+	}
+}
+
+
+/*
+ * The trap builtin.
+ */
+int
+trapcmd(int argc __unused, char **argv)
+{
+	char *action;
+	int signo;
+	int errors = 0;
+	int i;
+
+	while ((i = nextopt("l")) != '\0') {
+		switch (i) {
+		case 'l':
+			printsignals();
+			return (0);
+		}
+	}
+	argv = argptr;
+
+	if (*argv == NULL) {
+		for (signo = 0 ; signo < NSIG ; signo++) {
+			if (signo < NSIG && trap[signo] != NULL) {
+				out1str("trap -- ");
+				out1qstr(trap[signo]);
+				if (signo == 0) {
+					out1str(" EXIT\n");
+				} else if (sys_signame[signo]) {
+					out1fmt(" %s\n", sys_signame[signo]);
+				} else {
+					out1fmt(" %d\n", signo);
+				}
+			}
+		}
+		return 0;
+	}
+	action = NULL;
+	if (*argv && !is_number(*argv)) {
+		if (strcmp(*argv, "-") == 0)
+			argv++;
+		else {
+			action = *argv;
+			argv++;
+		}
+	}
+	for (; *argv; argv++) {
+		if ((signo = sigstring_to_signum(*argv)) == -1) {
+			warning("bad signal %s", *argv);
+			errors = 1;
+			continue;
+		}
+		INTOFF;
+		if (action)
+			action = savestr(action);
+		if (trap[signo])
+			ckfree(trap[signo]);
+		trap[signo] = action;
+		if (signo != 0)
+			setsignal(signo);
+		INTON;
+	}
+	return errors;
+}
+
+
+/*
+ * Clear traps on a fork.
+ */
+void
+clear_traps(void)
+{
+	char *volatile *tp;
+
+	for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
+			INTOFF;
+			ckfree(*tp);
+			*tp = NULL;
+			if (tp != &trap[0])
+				setsignal(tp - trap);
+			INTON;
+		}
+	}
+}
+
+
+/*
+ * Check if we have any traps enabled.
+ */
+int
+have_traps(void)
+{
+	char *volatile *tp;
+
+	for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+		if (*tp && **tp)	/* trap not NULL or SIG_IGN */
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Set the signal handler for the specified signal.  The routine figures
+ * out what it should be set to.
+ */
+void
+setsignal(int signo)
+{
+	int action;
+	sig_t sigact = SIG_DFL;
+	struct sigaction sa;
+	char *t;
+
+	if ((t = trap[signo]) == NULL)
+		action = S_DFL;
+	else if (*t != '\0')
+		action = S_CATCH;
+	else
+		action = S_IGN;
+	if (action == S_DFL) {
+		switch (signo) {
+		case SIGINT:
+			action = S_CATCH;
+			break;
+		case SIGQUIT:
+#ifdef DEBUG
+			{
+			extern int debug;
+
+			if (debug)
+				break;
+			}
+#endif
+			action = S_CATCH;
+			break;
+		case SIGTERM:
+			if (rootshell && iflag)
+				action = S_IGN;
+			break;
+#if JOBS
+		case SIGTSTP:
+		case SIGTTOU:
+			if (rootshell && mflag)
+				action = S_IGN;
+			break;
+#endif
+		}
+	}
+
+	t = &sigmode[signo];
+	if (*t == 0) {
+		/*
+		 * current setting unknown
+		 */
+		if (!getsigaction(signo, &sigact)) {
+			/*
+			 * Pretend it worked; maybe we should give a warning
+			 * here, but other shells don't. We don't alter
+			 * sigmode, so that we retry every time.
+			 */
+			return;
+		}
+		if (sigact == SIG_IGN) {
+			if (mflag && (signo == SIGTSTP ||
+			     signo == SIGTTIN || signo == SIGTTOU)) {
+				*t = S_IGN;	/* don't hard ignore these */
+			} else
+				*t = S_HARD_IGN;
+		} else {
+			*t = S_RESET;	/* force to be set */
+		}
+	}
+	if (*t == S_HARD_IGN || *t == action)
+		return;
+	switch (action) {
+		case S_DFL:	sigact = SIG_DFL;	break;
+		case S_CATCH:  	sigact = onsig;		break;
+		case S_IGN:	sigact = SIG_IGN;	break;
+	}
+	*t = action;
+	sa.sa_handler = sigact;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	sigaction(signo, &sa, NULL);
+}
+
+
+/*
+ * Return the current setting for sig w/o changing it.
+ */
+static int
+getsigaction(int signo, sig_t *sigact)
+{
+	struct sigaction sa;
+
+	if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
+		return 0;
+	*sigact = (sig_t) sa.sa_handler;
+	return 1;
+}
+
+
+/*
+ * Ignore a signal.
+ */
+void
+ignoresig(int signo)
+{
+
+	if (sigmode[signo] == 0)
+		setsignal(signo);
+	if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
+		signal(signo, SIG_IGN);
+		sigmode[signo] = S_IGN;
+	}
+}
+
+
+int
+issigchldtrapped(void)
+{
+
+	return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
+}
+
+
+/*
+ * Signal handler.
+ */
+void
+onsig(int signo)
+{
+
+	if (signo == SIGINT && trap[SIGINT] == NULL) {
+		/*
+		 * The !in_dotrap here is safe.  The only way we can arrive
+		 * here with in_dotrap set is that a trap handler set SIGINT to
+		 * SIG_DFL and killed itself.
+		 */
+		if (suppressint && !in_dotrap)
+			SET_PENDING_INT;
+		else
+			onint();
+		return;
+	}
+
+	/* If we are currently in a wait builtin, prepare to break it */
+	if (signo == SIGINT || signo == SIGQUIT)
+		pendingsig_waitcmd = signo;
+
+	if (trap[signo] != NULL && trap[signo][0] != '\0' &&
+	    (signo != SIGCHLD || !ignore_sigchld)) {
+		gotsig[signo] = 1;
+		pendingsig = signo;
+		pendingsig_waitcmd = signo;
+	}
+}
+
+
+/*
+ * Called to execute a trap.  Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+void
+dotrap(void)
+{
+	struct stackmark smark;
+	int i;
+	int savestatus, prev_evalskip, prev_skipcount;
+
+	in_dotrap++;
+	for (;;) {
+		pendingsig = 0;
+		pendingsig_waitcmd = 0;
+		for (i = 1; i < NSIG; i++) {
+			if (gotsig[i]) {
+				gotsig[i] = 0;
+				if (trap[i]) {
+					/*
+					 * Ignore SIGCHLD to avoid infinite
+					 * recursion if the trap action does
+					 * a fork.
+					 */
+					if (i == SIGCHLD)
+						ignore_sigchld++;
+
+					/*
+					 * Backup current evalskip
+					 * state and reset it before
+					 * executing a trap, so that the
+					 * trap is not disturbed by an
+					 * ongoing break/continue/return
+					 * statement.
+					 */
+					prev_evalskip  = evalskip;
+					prev_skipcount = skipcount;
+					evalskip = 0;
+
+					last_trapsig = i;
+					savestatus = exitstatus;
+					setstackmark(&smark);
+					evalstring(stsavestr(trap[i]), 0);
+					popstackmark(&smark);
+
+					/*
+					 * If such a command was not
+					 * already in progress, allow a
+					 * break/continue/return in the
+					 * trap action to have an effect
+					 * outside of it.
+					 */
+					if (evalskip == 0 ||
+					    prev_evalskip != 0) {
+						evalskip  = prev_evalskip;
+						skipcount = prev_skipcount;
+						exitstatus = savestatus;
+					}
+
+					if (i == SIGCHLD)
+						ignore_sigchld--;
+				}
+				break;
+			}
+		}
+		if (i >= NSIG)
+			break;
+	}
+	in_dotrap--;
+}
+
+
+/*
+ * Controls whether the shell is interactive or not based on iflag.
+ */
+void
+setinteractive(void)
+{
+	setsignal(SIGINT);
+	setsignal(SIGQUIT);
+	setsignal(SIGTERM);
+}
+
+
+/*
+ * Called to exit the shell.
+ */
+void
+exitshell(int status)
+{
+	TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
+	exiting = 1;
+	exiting_exitstatus = status;
+	exitshell_savedstatus();
+}
+
+void
+exitshell_savedstatus(void)
+{
+	struct jmploc loc1, loc2;
+	char *p;
+	int sig = 0;
+	sigset_t sigs;
+
+	if (!exiting) {
+		if (in_dotrap && last_trapsig) {
+			sig = last_trapsig;
+			exiting_exitstatus = sig + 128;
+		} else
+			exiting_exitstatus = oexitstatus;
+	}
+	exitstatus = oexitstatus = exiting_exitstatus;
+	if (!setjmp(loc1.loc)) {
+		handler = &loc1;
+		if ((p = trap[0]) != NULL && *p != '\0') {
+			/*
+			 * Reset evalskip, or the trap on EXIT could be
+			 * interrupted if the last command was a "return".
+			 */
+			evalskip = 0;
+			trap[0] = NULL;
+			FORCEINTON;
+			evalstring(p, 0);
+		}
+	}
+	if (!setjmp(loc2.loc)) {
+		handler = &loc2;		/* probably unnecessary */
+		FORCEINTON;
+		flushall();
+#if JOBS
+		setjobctl(0);
+#endif
+	}
+	if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
+	    sig != SIGTTOU) {
+		signal(sig, SIG_DFL);
+		sigemptyset(&sigs);
+		sigaddset(&sigs, sig);
+		sigprocmask(SIG_UNBLOCK, &sigs, NULL);
+		kill(getpid(), sig);
+		/* If the default action is to ignore, fall back to _exit(). */
+	}
+	_exit(exiting_exitstatus);
+}
diff --git a/bin/1sh/trap.h b/bin/1sh/trap.h
new file mode 100644
index 00000000..75427d56
--- /dev/null
+++ b/bin/1sh/trap.h
@@ -0,0 +1,50 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)trap.h	8.3 (Berkeley) 6/5/95
+ * $FreeBSD: releng/12.1/bin/sh/trap.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+extern volatile sig_atomic_t pendingsig;
+extern volatile sig_atomic_t pendingsig_waitcmd;
+
+void clear_traps(void);
+int have_traps(void);
+void setsignal(int);
+void ignoresig(int);
+int issigchldtrapped(void);
+void onsig(int);
+void dotrap(void);
+void setinteractive(void);
+void exitshell(int) __attribute__((noreturn));
+void exitshell_savedstatus(void) __attribute__((noreturn));
diff --git a/bin/1sh/var.c b/bin/1sh/var.c
new file mode 100644
index 00000000..44742169
--- /dev/null
+++ b/bin/1sh/var.c
@@ -0,0 +1,983 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* $FreeBSD: releng/12.1/bin/sh/var.c 329221 2018-02-13 16:48:57Z bdrewery $ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <paths.h>
+
+/*
+ * Shell variables.
+ */
+
+#include <locale.h>
+#include <langinfo.h>
+
+#include "shell.h"
+#include "output.h"
+#include "expand.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"	/* defines cmdenviron */
+#include "exec.h"
+#include "syntax.h"
+#include "options.h"
+#include "mail.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "parser.h"
+#include "builtins.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+
+#ifndef VTABSIZE
+#define VTABSIZE 39
+#endif
+
+
+struct varinit {
+	struct var *var;
+	int flags;
+	const char *text;
+	void (*func)(const char *);
+};
+
+
+#ifndef NO_HISTORY
+struct var vhistfile;
+struct var vhistsize;
+struct var vterm;
+#endif
+struct var vifs;
+struct var vmail;
+struct var vmpath;
+struct var vpath;
+struct var vps0;
+struct var vps1;
+struct var vps2;
+struct var vps4;
+struct var vrps1;
+struct var vrps2;
+static struct var voptind;
+struct var vdisvfork;
+
+struct localvar *localvars;
+int forcelocal;
+
+static const struct varinit varinit[] = {
+#ifndef NO_HISTORY
+	{ &vhistfile,	VUNSET,				"HISTFILE=",
+	  sethistfile },
+	{ &vhistsize,	VUNSET,				"HISTSIZE=",
+	  sethistsize },
+#endif
+	{ &vifs,	0,				"IFS= \t\n",
+	  NULL },
+	{ &vmail,	VUNSET,				"MAIL=",
+	  NULL },
+	{ &vmpath,	VUNSET,				"MAILPATH=",
+	  NULL },
+	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
+	  changepath },
+	{ &vps0,	VUNSET,				"PS0=",
+	  NULL },
+	/*
+	 * vps1 depends on uid
+	 */
+	{ &vps2,	0,				"PS2=> ",
+	  NULL },
+	{ &vps4,	0,				"PS4=+ ",
+	  NULL },
+	{ &vrps1,	VUNSET,				"RPS1=",
+	  NULL },
+	{ &vrps2,	VUNSET,				"RPS2=",
+	  NULL },
+#ifndef NO_HISTORY
+	{ &vterm,	VUNSET,				"TERM=",
+	  setterm },
+#endif
+	{ &voptind,	0,				"OPTIND=1",
+	  getoptsreset },
+	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
+	  NULL },
+	{ NULL,	0,				NULL,
+	  NULL }
+};
+
+static struct var *vartab[VTABSIZE];
+
+static const char *const locale_names[7] = {
+	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
+	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
+};
+static const int locale_categories[7] = {
+	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
+};
+
+static int varequal(const char *, const char *);
+static struct var *find_var(const char *, struct var ***, int *);
+static int localevar(const char *);
+static void setvareq_const(const char *s, int flags);
+
+extern char **environ;
+
+/*
+ * This routine initializes the builtin variables and imports the environment.
+ * It is called when the shell is initialized.
+ */
+
+void
+initvar(void)
+{
+	char ppid[20];
+	const struct varinit *ip;
+	struct var *vp;
+	struct var **vpp;
+	char **envp;
+
+	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
+		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
+			continue;
+		vp->next = *vpp;
+		*vpp = vp;
+		vp->text = (char *)(ip->text);
+		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
+		vp->func = ip->func;
+	}
+	/*
+	 * PS1 depends on uid
+	 */
+	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
+		vps1.next = *vpp;
+		*vpp = &vps1;
+		vps1.text = (char *)(geteuid() ? "PS1=$ " : "PS1=# ");
+		vps1.flags = VSTRFIXED|VTEXTFIXED;
+	}
+	fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
+	setvarsafe("PPID", ppid, 0);
+	for (envp = environ ; *envp ; envp++) {
+		if (strchr(*envp, '=')) {
+			setvareq(*envp, VEXPORT|VTEXTFIXED);
+		}
+	}
+	setvareq_const("OPTIND=1", 0);
+	setvareq_const("IFS= \t\n", 0);
+}
+
+/*
+ * Safe version of setvar, returns 1 on success 0 on failure.
+ */
+
+int
+setvarsafe(const char *name, const char *val, int flags)
+{
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	int err = 0;
+	int inton;
+
+	inton = is_int_on();
+	if (setjmp(jmploc.loc))
+		err = 1;
+	else {
+		handler = &jmploc;
+		setvar(name, val, flags);
+	}
+	handler = savehandler;
+	SETINTON(inton);
+	return err;
+}
+
+/*
+ * Set the value of a variable.  The flags argument is stored with the
+ * flags of the variable.  If val is NULL, the variable is unset.
+ */
+
+void
+setvar(const char *name, const char *val, int flags)
+{
+	const char *p;
+	size_t len;
+	size_t namelen;
+	size_t vallen;
+	char *nameeq;
+	int isbad;
+
+	isbad = 0;
+	p = name;
+	if (! is_name(*p))
+		isbad = 1;
+	p++;
+	for (;;) {
+		if (! is_in_name(*p)) {
+			if (*p == '\0' || *p == '=')
+				break;
+			isbad = 1;
+		}
+		p++;
+	}
+	namelen = p - name;
+	if (isbad)
+		error("%.*s: bad variable name", (int)namelen, name);
+	len = namelen + 2;		/* 2 is space for '=' and '\0' */
+	if (val == NULL) {
+		flags |= VUNSET;
+		vallen = 0;
+	} else {
+		vallen = strlen(val);
+		len += vallen;
+	}
+	INTOFF;
+	nameeq = ckmalloc(len);
+	memcpy(nameeq, name, namelen);
+	nameeq[namelen] = '=';
+	if (val)
+		memcpy(nameeq + namelen + 1, val, vallen + 1);
+	else
+		nameeq[namelen + 1] = '\0';
+	setvareq(nameeq, flags);
+	INTON;
+}
+
+static int
+localevar(const char *s)
+{
+	const char *const *ss;
+
+	if (*s != 'L')
+		return 0;
+	if (varequal(s + 1, "ANG"))
+		return 1;
+	if (strncmp(s + 1, "C_", 2) != 0)
+		return 0;
+	if (varequal(s + 3, "ALL"))
+		return 1;
+	for (ss = locale_names; *ss ; ss++)
+		if (varequal(s + 3, *ss + 3))
+			return 1;
+	return 0;
+}
+
+
+/*
+ * Sets/unsets an environment variable from a pointer that may actually be a
+ * pointer into environ where the string should not be manipulated.
+ */
+static void
+change_env(const char *s, int set)
+{
+	char *eqp;
+	char *ss;
+
+	INTOFF;
+	ss = savestr(s);
+	if ((eqp = strchr(ss, '=')) != NULL)
+		*eqp = '\0';
+	if (set && eqp != NULL)
+		(void) setenv(ss, eqp + 1, 1);
+	else
+		(void) unsetenv(ss);
+	ckfree(ss);
+	INTON;
+
+	return;
+}
+
+
+/*
+ * Same as setvar except that the variable and value are passed in
+ * the first argument as name=value.  Since the first argument will
+ * be actually stored in the table, it should not be a string that
+ * will go away.
+ */
+
+void
+setvareq(char *s, int flags)
+{
+	struct var *vp, **vpp;
+	int nlen;
+
+	if (aflag)
+		flags |= VEXPORT;
+	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
+		mklocal(s);
+	vp = find_var(s, &vpp, &nlen);
+	if (vp != NULL) {
+		if (vp->flags & VREADONLY) {
+			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(s);
+			error("%.*s: is read only", vp->name_len, vp->text);
+		}
+		if (flags & VNOSET) {
+			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(s);
+			return;
+		}
+		INTOFF;
+
+		if (vp->func && (flags & VNOFUNC) == 0)
+			(*vp->func)(s + vp->name_len + 1);
+
+		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(vp->text);
+
+		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
+		vp->flags |= flags;
+		vp->text = s;
+
+		/*
+		 * We could roll this to a function, to handle it as
+		 * a regular variable function callback, but why bother?
+		 *
+		 * Note: this assumes iflag is not set to 1 initially.
+		 * As part of initvar(), this is called before arguments
+		 * are looked at.
+		 */
+		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
+		    iflag == 1)
+			chkmail(1);
+		if ((vp->flags & VEXPORT) && localevar(s)) {
+			change_env(s, 1);
+			(void) setlocale(LC_ALL, "");
+			updatecharset();
+		}
+		INTON;
+		return;
+	}
+	/* not found */
+	if (flags & VNOSET) {
+		if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(s);
+		return;
+	}
+	INTOFF;
+	vp = ckmalloc(sizeof (*vp));
+	vp->flags = flags;
+	vp->text = s;
+	vp->name_len = nlen;
+	vp->next = *vpp;
+	vp->func = NULL;
+	*vpp = vp;
+	if ((vp->flags & VEXPORT) && localevar(s)) {
+		change_env(s, 1);
+		(void) setlocale(LC_ALL, "");
+		updatecharset();
+	}
+	INTON;
+}
+
+
+static void
+setvareq_const(const char *s, int flags)
+{
+	setvareq((char *)(s), flags | VTEXTFIXED);
+}
+
+
+/*
+ * Process a linked list of variable assignments.
+ */
+
+void
+listsetvar(struct arglist *list, int flags)
+{
+	int i;
+
+	INTOFF;
+	for (i = 0; i < list->count; i++)
+		setvareq(savestr(list->args[i]), flags);
+	INTON;
+}
+
+
+
+/*
+ * Find the value of a variable.  Returns NULL if not set.
+ */
+
+char *
+lookupvar(const char *name)
+{
+	struct var *v;
+
+	v = find_var(name, NULL, NULL);
+	if (v == NULL || v->flags & VUNSET)
+		return NULL;
+	return v->text + v->name_len + 1;
+}
+
+
+
+/*
+ * Search the environment of a builtin command.  If the second argument
+ * is nonzero, return the value of a variable even if it hasn't been
+ * exported.
+ */
+
+char *
+bltinlookup(const char *name, int doall)
+{
+	struct var *v;
+	char *result;
+	int i;
+
+	result = NULL;
+	if (cmdenviron) for (i = 0; i < cmdenviron->count; i++) {
+		if (varequal(cmdenviron->args[i], name))
+			result = strchr(cmdenviron->args[i], '=') + 1;
+	}
+	if (result != NULL)
+		return result;
+
+	v = find_var(name, NULL, NULL);
+	if (v == NULL || v->flags & VUNSET ||
+	    (!doall && (v->flags & VEXPORT) == 0))
+		return NULL;
+	return v->text + v->name_len + 1;
+}
+
+
+/*
+ * Set up locale for a builtin (LANG/LC_* assignments).
+ */
+void
+bltinsetlocale(void)
+{
+	int act = 0;
+	char *loc, *locdef;
+	int i;
+
+	if (cmdenviron) for (i = 0; i < cmdenviron->count; i++) {
+		if (localevar(cmdenviron->args[i])) {
+			act = 1;
+			break;
+		}
+	}
+	if (!act)
+		return;
+	loc = bltinlookup("LC_ALL", 0);
+	INTOFF;
+	if (loc != NULL) {
+		setlocale(LC_ALL, loc);
+		INTON;
+		updatecharset();
+		return;
+	}
+	locdef = bltinlookup("LANG", 0);
+	for (i = 0; locale_names[i] != NULL; i++) {
+		loc = bltinlookup(locale_names[i], 0);
+		if (loc == NULL)
+			loc = locdef;
+		if (loc != NULL)
+			setlocale(locale_categories[i], loc);
+	}
+	INTON;
+	updatecharset();
+}
+
+/*
+ * Undo the effect of bltinlocaleset().
+ */
+void
+bltinunsetlocale(void)
+{
+	int i;
+
+	INTOFF;
+	if (cmdenviron) for (i = 0; i < cmdenviron->count; i++) {
+		if (localevar(cmdenviron->args[i])) {
+			setlocale(LC_ALL, "");
+			updatecharset();
+			break;
+		}
+	}
+	INTON;
+}
+
+/*
+ * Update the localeisutf8 flag.
+ */
+void
+updatecharset(void)
+{
+	char *charset;
+
+	charset = nl_langinfo(CODESET);
+	localeisutf8 = !strcmp(charset, "UTF-8");
+}
+
+void
+initcharset(void)
+{
+	updatecharset();
+	initial_localeisutf8 = localeisutf8;
+}
+
+/*
+ * Generate a list of exported variables.  This routine is used to construct
+ * the third argument to execve when executing a program.
+ */
+
+char **
+environment(void)
+{
+	int nenv;
+	struct var **vpp;
+	struct var *vp;
+	char **env, **ep;
+
+	nenv = 0;
+	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if (vp->flags & VEXPORT)
+				nenv++;
+	}
+	ep = env = stalloc((nenv + 1) * sizeof *env);
+	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if (vp->flags & VEXPORT)
+				*ep++ = vp->text;
+	}
+	*ep = NULL;
+	return env;
+}
+
+
+static int
+var_compare(const void *a, const void *b)
+{
+	const char *const *sa, *const *sb;
+
+	sa = a;
+	sb = b;
+	/*
+	 * This compares two var=value strings which creates a different
+	 * order from what you would probably expect.  POSIX is somewhat
+	 * ambiguous on what should be sorted exactly.
+	 */
+	return strcoll(*sa, *sb);
+}
+
+
+/*
+ * Command to list all variables which are set.  This is invoked from the
+ * set command when it is called without any options or operands.
+ */
+
+int
+showvarscmd(int argc __unused, char **argv __unused)
+{
+	struct var **vpp;
+	struct var *vp;
+	const char *s;
+	const char **vars;
+	int i, n;
+
+	/*
+	 * POSIX requires us to sort the variables.
+	 */
+	n = 0;
+	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
+		for (vp = *vpp; vp; vp = vp->next) {
+			if (!(vp->flags & VUNSET))
+				n++;
+		}
+	}
+
+	INTOFF;
+	vars = ckmalloc(n * sizeof(*vars));
+	i = 0;
+	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
+		for (vp = *vpp; vp; vp = vp->next) {
+			if (!(vp->flags & VUNSET))
+				vars[i++] = vp->text;
+		}
+	}
+
+	qsort(vars, n, sizeof(*vars), var_compare);
+	for (i = 0; i < n; i++) {
+		/*
+		 * Skip improper variable names so the output remains usable as
+		 * shell input.
+		 */
+		if (!isassignment(vars[i]))
+			continue;
+		s = strchr(vars[i], '=');
+		s++;
+		outbin(vars[i], s - vars[i], out1);
+		out1qstr(s);
+		out1c('\n');
+	}
+	ckfree(vars);
+	INTON;
+
+	return 0;
+}
+
+
+
+/*
+ * The export and readonly commands.
+ */
+
+int
+exportcmd(int argc __unused, char **argv)
+{
+	struct var **vpp;
+	struct var *vp;
+	char **ap;
+	char *name;
+	char *p;
+	char *cmdname;
+	int ch, values;
+	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
+
+	cmdname = argv[0];
+	values = 0;
+	while ((ch = nextopt("p")) != '\0') {
+		switch (ch) {
+		case 'p':
+			values = 1;
+			break;
+		}
+	}
+
+	if (values && *argptr != NULL)
+		error("-p requires no arguments");
+	if (*argptr != NULL) {
+		for (ap = argptr; (name = *ap) != NULL; ap++) {
+			if ((p = strchr(name, '=')) != NULL) {
+				p++;
+			} else {
+				vp = find_var(name, NULL, NULL);
+				if (vp != NULL) {
+					vp->flags |= flag;
+					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+						change_env(vp->text, 1);
+						(void) setlocale(LC_ALL, "");
+						updatecharset();
+					}
+					continue;
+				}
+			}
+			setvar(name, p, flag);
+		}
+	} else {
+		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+			for (vp = *vpp ; vp ; vp = vp->next) {
+				if (vp->flags & flag) {
+					if (values) {
+						/*
+						 * Skip improper variable names
+						 * so the output remains usable
+						 * as shell input.
+						 */
+						if (!isassignment(vp->text))
+							continue;
+						out1str(cmdname);
+						out1c(' ');
+					}
+					if (values && !(vp->flags & VUNSET)) {
+						outbin(vp->text,
+						    vp->name_len + 1, out1);
+						out1qstr(vp->text +
+						    vp->name_len + 1);
+					} else
+						outbin(vp->text, vp->name_len,
+						    out1);
+					out1c('\n');
+				}
+			}
+		}
+	}
+	return 0;
+}
+
+
+/*
+ * The "local" command.
+ */
+
+int
+localcmd(int argc __unused, char **argv __unused)
+{
+	char *name;
+
+	nextopt("");
+	if (! in_function())
+		error("Not in a function");
+	while ((name = *argptr++) != NULL) {
+		mklocal(name);
+	}
+	return 0;
+}
+
+
+/*
+ * Make a variable a local variable.  When a variable is made local, it's
+ * value and flags are saved in a localvar structure.  The saved values
+ * will be restored when the shell function returns.  We handle the name
+ * "-" as a special case.
+ */
+
+void
+mklocal(char *name)
+{
+	struct localvar *lvp;
+	struct var **vpp;
+	struct var *vp;
+
+	INTOFF;
+	lvp = ckmalloc(sizeof (struct localvar));
+	if (name[0] == '-' && name[1] == '\0') {
+		lvp->text = ckmalloc(sizeof optval);
+		memcpy(lvp->text, optval, sizeof optval);
+		vp = NULL;
+	} else {
+		vp = find_var(name, &vpp, NULL);
+		if (vp == NULL) {
+			if (strchr(name, '='))
+				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
+			else
+				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
+			vp = *vpp;	/* the new variable */
+			lvp->text = NULL;
+			lvp->flags = VUNSET;
+		} else {
+			lvp->text = vp->text;
+			lvp->flags = vp->flags;
+			vp->flags |= VSTRFIXED|VTEXTFIXED;
+			if (name[vp->name_len] == '=')
+				setvareq(savestr(name), VNOLOCAL);
+		}
+	}
+	lvp->vp = vp;
+	lvp->next = localvars;
+	localvars = lvp;
+	INTON;
+}
+
+
+/*
+ * Called after a function returns.
+ */
+
+void
+poplocalvars(void)
+{
+	struct localvar *lvp;
+	struct var *vp;
+	int islocalevar;
+
+	INTOFF;
+	while ((lvp = localvars) != NULL) {
+		localvars = lvp->next;
+		vp = lvp->vp;
+		if (vp == NULL) {	/* $- saved */
+			memcpy(optval, lvp->text, sizeof optval);
+			ckfree(lvp->text);
+			optschanged();
+		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
+			vp->flags &= ~VREADONLY;
+			(void)unsetvar(vp->text);
+		} else {
+			islocalevar = (vp->flags | lvp->flags) & VEXPORT &&
+			    localevar(lvp->text);
+			if ((vp->flags & VTEXTFIXED) == 0)
+				ckfree(vp->text);
+			vp->flags = lvp->flags;
+			vp->text = lvp->text;
+			if (vp->func)
+				(*vp->func)(vp->text + vp->name_len + 1);
+			if (islocalevar) {
+				change_env(vp->text, vp->flags & VEXPORT &&
+				    (vp->flags & VUNSET) == 0);
+				setlocale(LC_ALL, "");
+				updatecharset();
+			}
+		}
+		ckfree(lvp);
+	}
+	INTON;
+}
+
+
+int
+setvarcmd(int argc, char **argv)
+{
+	if (argc <= 2)
+		return unsetcmd(argc, argv);
+	else if (argc == 3)
+		setvar(argv[1], argv[2], 0);
+	else
+		error("too many arguments");
+	return 0;
+}
+
+
+/*
+ * The unset builtin command.
+ */
+
+int
+unsetcmd(int argc __unused, char **argv __unused)
+{
+	char **ap;
+	int i;
+	int flg_func = 0;
+	int flg_var = 0;
+	int ret = 0;
+
+	while ((i = nextopt("vf")) != '\0') {
+		if (i == 'f')
+			flg_func = 1;
+		else
+			flg_var = 1;
+	}
+	if (flg_func == 0 && flg_var == 0)
+		flg_var = 1;
+
+	INTOFF;
+	for (ap = argptr; *ap ; ap++) {
+		if (flg_func)
+			ret |= unsetfunc(*ap);
+		if (flg_var)
+			ret |= unsetvar(*ap);
+	}
+	INTON;
+	return ret;
+}
+
+
+/*
+ * Unset the specified variable.
+ * Called with interrupts off.
+ */
+
+int
+unsetvar(const char *s)
+{
+	struct var **vpp;
+	struct var *vp;
+
+	vp = find_var(s, &vpp, NULL);
+	if (vp == NULL)
+		return (0);
+	if (vp->flags & VREADONLY)
+		return (1);
+	if (vp->text[vp->name_len + 1] != '\0')
+		setvar(s, "", 0);
+	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+		change_env(s, 0);
+		setlocale(LC_ALL, "");
+		updatecharset();
+	}
+	vp->flags &= ~VEXPORT;
+	vp->flags |= VUNSET;
+	if ((vp->flags & VSTRFIXED) == 0) {
+		if ((vp->flags & VTEXTFIXED) == 0)
+			ckfree(vp->text);
+		*vpp = vp->next;
+		ckfree(vp);
+	}
+	return (0);
+}
+
+
+
+/*
+ * Returns true if the two strings specify the same variable.  The first
+ * variable name is terminated by '='; the second may be terminated by
+ * either '=' or '\0'.
+ */
+
+static int
+varequal(const char *p, const char *q)
+{
+	while (*p == *q++) {
+		if (*p++ == '=')
+			return 1;
+	}
+	if (*p == '=' && *(q - 1) == '\0')
+		return 1;
+	return 0;
+}
+
+/*
+ * Search for a variable.
+ * 'name' may be terminated by '=' or a NUL.
+ * vppp is set to the pointer to vp, or the list head if vp isn't found
+ * lenp is set to the number of characters in 'name'
+ */
+
+static struct var *
+find_var(const char *name, struct var ***vppp, int *lenp)
+{
+	unsigned int hashval;
+	int len;
+	struct var *vp, **vpp;
+	const char *p = name;
+
+	hashval = 0;
+	while (*p && *p != '=')
+		hashval = 2 * hashval + (unsigned char)*p++;
+	len = p - name;
+
+	if (lenp)
+		*lenp = len;
+	vpp = &vartab[hashval % VTABSIZE];
+	if (vppp)
+		*vppp = vpp;
+
+	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
+		if (vp->name_len != len)
+			continue;
+		if (memcmp(vp->text, name, len) != 0)
+			continue;
+		if (vppp)
+			*vppp = vpp;
+		return vp;
+	}
+	return NULL;
+}
diff --git a/bin/1sh/var.h b/bin/1sh/var.h
new file mode 100644
index 00000000..d06d8688
--- /dev/null
+++ b/bin/1sh/var.h
@@ -0,0 +1,140 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)var.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: releng/12.1/bin/sh/var.h 326025 2017-11-20 19:49:47Z pfg $
+ */
+
+/*
+ * Shell variables.
+ */
+
+/* flags */
+#define VEXPORT		0x01	/* variable is exported */
+#define VREADONLY	0x02	/* variable cannot be modified */
+#define VSTRFIXED	0x04	/* variable struct is statically allocated */
+#define VTEXTFIXED	0x08	/* text is statically allocated */
+#define VSTACK		0x10	/* text is allocated on the stack */
+#define VUNSET		0x20	/* the variable is not set */
+#define VNOFUNC		0x40	/* don't call the callback function */
+#define VNOSET		0x80	/* do not set variable - just readonly test */
+#define VNOLOCAL	0x100	/* ignore forcelocal */
+
+
+struct var {
+	struct var *next;		/* next entry in hash list */
+	int flags;			/* flags are defined above */
+	int name_len;			/* length of name */
+	char *text;			/* name=value */
+	void (*func)(const char *);
+					/* function to be called when  */
+					/* the variable gets set/unset */
+};
+
+
+struct localvar {
+	struct localvar *next;		/* next local variable in list */
+	struct var *vp;			/* the variable that was made local */
+	int flags;			/* saved flags */
+	char *text;			/* saved text */
+};
+
+
+extern struct localvar *localvars;
+extern int forcelocal;
+
+extern struct var vifs;
+extern struct var vmail;
+extern struct var vmpath;
+extern struct var vpath;
+extern struct var vps0;
+extern struct var vps1;
+extern struct var vps2;
+extern struct var vps4;
+extern struct var vrps1;
+extern struct var vrps2;
+extern struct var vdisvfork;
+#ifndef NO_HISTORY
+extern struct var vhistfile;
+extern struct var vhistsize;
+extern struct var vterm;
+#endif
+
+extern int localeisutf8;
+/* The parser uses the locale that was in effect at startup. */
+extern int initial_localeisutf8;
+
+/*
+ * The following macros access the values of the above variables.
+ * They have to skip over the name.  They return the null string
+ * for unset variables.
+ */
+
+#define ifsval()	(vifs.text + 4)
+#define ifsset()	((vifs.flags & VUNSET) == 0)
+#define mailval()	(vmail.text + 5)
+#define mpathval()	(vmpath.text + 9)
+#define pathval()	(vpath.text + 5)
+#define ps0val()	(vps0.text + 4)
+#define ps1val()	(vps1.text + 4)
+#define ps2val()	(vps2.text + 4)
+#define ps4val()	(vps4.text + 4)
+#define rps1val()	(vrps1.text + 5)
+#define rps2val()	(vrps2.text + 5)
+#define optindval()	(voptind.text + 7)
+#ifndef NO_HISTORY
+#define histfileval()	(vhistfile.text + 9)
+#define histsizeval()	(vhistsize.text + 9)
+#define termval()	(vterm.text + 5)
+#endif
+
+#define mpathset()	((vmpath.flags & VUNSET) == 0)
+#define disvforkset()	((vdisvfork.flags & VUNSET) == 0)
+
+void initvar(void);
+void setvar(const char *, const char *, int);
+void setvareq(char *, int);
+struct arglist;
+void listsetvar(struct arglist *, int);
+char *lookupvar(const char *);
+char *bltinlookup(const char *, int);
+void bltinsetlocale(void);
+void bltinunsetlocale(void);
+void updatecharset(void);
+void initcharset(void);
+char **environment(void);
+int showvarscmd(int, char **);
+void mklocal(char *);
+void poplocalvars(void);
+int unsetvar(const char *);
+int setvarsafe(const char *, const char *, int);
diff --git a/bin/LICENSE b/bin/LICENSE
new file mode 100644
index 00000000..dba13ed2
--- /dev/null
+++ b/bin/LICENSE
@@ -0,0 +1,661 @@
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU Affero General Public License is a free, copyleft license for
+software and other kinds of works, specifically designed to ensure
+cooperation with the community in the case of network server software.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+our General Public Licenses are intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  Developers that use our General Public Licenses protect your rights
+with two steps: (1) assert copyright on the software, and (2) offer
+you this License which gives you legal permission to copy, distribute
+and/or modify the software.
+
+  A secondary benefit of defending all users' freedom is that
+improvements made in alternate versions of the program, if they
+receive widespread use, become available for other developers to
+incorporate.  Many developers of free software are heartened and
+encouraged by the resulting cooperation.  However, in the case of
+software used on network servers, this result may fail to come about.
+The GNU General Public License permits making a modified version and
+letting the public access it on a server without ever releasing its
+source code to the public.
+
+  The GNU Affero General Public License is designed specifically to
+ensure that, in such cases, the modified source code becomes available
+to the community.  It requires the operator of a network server to
+provide the source code of the modified version running there to the
+users of that server.  Therefore, public use of a modified version, on
+a publicly accessible server, gives the public access to the source
+code of the modified version.
+
+  An older license, called the Affero General Public License and
+published by Affero, was designed to accomplish similar goals.  This is
+a different license, not a version of the Affero GPL, but Affero has
+released a new version of the Affero GPL which permits relicensing under
+this license.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU Affero General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
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+conditions are met.  This License explicitly affirms your unlimited
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+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
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+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
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+  You may convey verbatim copies of the Program's source code as you
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+and you may offer support or warranty protection for a fee.
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+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
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+  You may convey a covered work in object code form under the terms
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+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
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+
+  Notwithstanding any other provision of this License, for material you
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+that material) supplement the terms of this License with terms:
+
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+    terms of sections 15 and 16 of this License; or
+
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+    Notices displayed by works containing it; or
+
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+    material by anyone who conveys the material (or modified versions of
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+  All other non-permissive additional terms are considered "further
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+  You may not propagate or modify a covered work except as expressly
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+  However, if you cease all violation of this License, then your
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+  Termination of your rights under this section does not terminate the
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+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
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+  10. Automatic Licensing of Downstream Recipients.
+
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+
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+
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+(such as an express permission to practice a patent or covenant not to
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+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
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+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
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+
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+arrangement, you convey, or propagate by procuring conveyance of, a
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+receiving the covered work authorizing them to use, propagate, modify
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+you grant is automatically extended to all recipients of the covered
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+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
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+in the business of distributing software, under which you make payment
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+parties who would receive the covered work from you, a discriminatory
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+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
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+the Program, the only way you could satisfy both those terms and this
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+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
+interacting with it remotely through a computer network (if your version
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+
+  Notwithstanding any other provision of this License, you have
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+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
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+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
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+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
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+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
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+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
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+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
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+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
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+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<http://www.gnu.org/licenses/>.
diff --git a/bin/Makefile b/bin/Makefile
new file mode 100644
index 00000000..5691b0fc
--- /dev/null
+++ b/bin/Makefile
@@ -0,0 +1,153 @@
+PREFIX = ~/.local
+MANDIR = ${PREFIX}/share/man
+
+LIBS_PREFIX = /usr/local
+CFLAGS += -I${LIBS_PREFIX}/include
+LDFLAGS += -L${LIBS_PREFIX}/lib
+
+CFLAGS += -Wall -Wextra -Wpedantic -Wno-gnu-case-range
+LDLIBS.dtch = -lutil
+LDLIBS.fbclock = -lz
+LDLIBS.glitch = -lz
+LDLIBS.hnel = -lutil
+LDLIBS.modem = -lutil
+LDLIBS.pngo = -lz
+LDLIBS.ptee = -lutil
+LDLIBS.relay = -ltls
+LDLIBS.scheme = -lm
+LDLIBS.title = -lcurl
+
+-include config.mk
+
+BINS += beef
+BINS += bibsort
+BINS += bit
+BINS += c
+BINS += dtch
+BINS += glitch
+BINS += hi
+BINS += hnel
+BINS += modem
+BINS += nudge
+BINS += order
+BINS += pbd
+BINS += pngo
+BINS += psf2png
+BINS += ptee
+BINS += scheme
+BINS += shotty
+BINS += title
+BINS += ttpre
+BINS += up
+BINS += when
+BINS += xx
+
+LINKS += open
+LINKS += pbcopy
+LINKS += pbpaste
+
+BINS_BSD += ever
+BINS_LINUX += bri
+BINS_LINUX += fbatt
+BINS_LINUX += fbclock
+BINS_LINUX += psfed
+BINS_TLS += relay
+
+BINS_ALL = ${BINS} ${BINS_BSD} ${BINS_LINUX} ${BINS_TLS}
+MANS_ALL = ${BINS_ALL:%=man1/%.1}
+
+any: meta ${BINS} ${LINKS}
+
+bsd: meta ${BINS_BSD}
+
+linux: meta ${BINS_LINUX}
+
+tls: meta ${BINS_TLS}
+
+meta: .gitignore tags
+
+.SUFFIXES: .pl
+
+.c:
+	${CC} ${CFLAGS} ${LDFLAGS} $< ${LDLIBS.$@} -o $@
+
+.o:
+	${CC} ${LDFLAGS} $< ${LDLIBS.$@} -o $@
+
+.pl:
+	cp -f $< $@
+	chmod a+x $@
+
+hi: hi.c
+	${CC} ${CFLAGS} ${LDFLAGS} hi.c ${LDLIBS.$@} -o $@
+	./hi -c
+
+open pbcopy pbpaste: pbd
+	ln -f pbd $@
+
+fbatt.o fbclock.o: scheme.h
+
+psf2png.o scheme.o: png.h
+
+scheme.h: scheme
+	./scheme -c > scheme.h
+
+tags: *.h *.c
+	ctags -w *.h *.c
+
+IGNORE = *.o *.html ${BINS_ALL} ${LINKS} scheme.h tags
+
+.gitignore: Makefile
+	echo config.mk '${IGNORE}' | tr ' ' '\n' | sort > .gitignore
+
+clean:
+	rm -f ${IGNORE}
+
+setuid: bri
+	chown root bri
+	chmod u+s bri
+
+link:
+	install -d ${PREFIX}/bin ${MANDIR}/man1
+	ln -fs ${BINS_ALL:%=${PWD}/%} ${PREFIX}/bin
+	ln -fs ${MANS_ALL:%=${PWD}/%} ${MANDIR}/man1
+	ln -fs ${LINKS:%=${PWD}/%} ${PREFIX}/bin
+
+unlink:
+	rm -f ${BINS_ALL:%=${PREFIX}/bin/%}
+	rm -f ${MANS_ALL:%=${MANDIR}/%}
+	rm -f ${LINKS:%=${PREFIX}/bin/%}
+
+HTMLS = index.html ${BINS_ALL:=.html} png.html
+WEBROOT = /usr/local/www/causal.agency
+
+html: ${HTMLS}
+	@true
+
+${HTMLS}: html.sh scheme hi ttpre
+
+.SUFFIXES: .html
+
+.c.html:
+	sh html.sh $< man1/${<:.c=.1} > $@
+
+.h.html:
+	sh html.sh $< man3/${<:.h=.3} > $@
+
+.y.html:
+	sh html.sh $< man1/${<:.y=.1} > $@
+
+.sh.html:
+	sh html.sh $< man1/${<:.sh=.1} > $@
+
+.pl.html:
+	sh html.sh $< man1/${<:.pl=.1} > $@
+
+index.html: Makefile README.7
+	sh html.sh Makefile README.7 \
+		| sed -E 's,([a-z0-9-]+)[(][1-9][)],<a href="\1.html">&</a>,' \
+		> index.html
+
+install-html: ${HTMLS}
+	install -d ${WEBROOT}/bin
+	install -C -m 644 ${HTMLS} ${WEBROOT}/bin
diff --git a/bin/README.7 b/bin/README.7
new file mode 100644
index 00000000..40dcdd0b
--- /dev/null
+++ b/bin/README.7
@@ -0,0 +1,83 @@
+.Dd December 15, 2020
+.Dt BIN 7
+.Os "Causal Agency"
+.
+.Sh NAME
+.Nm bin
+.Nd various utilities
+.
+.Sh DESCRIPTION
+Various tools primarily targeting
+Darwin,
+.Fx
+and
+.Nx .
+Some tools target Linux.
+.
+.Pp
+.Bl -tag -width "fbclock(1)" -compact
+.It Xr beef 1
+Befunge-93 interpreter
+.It Xr bibsort 1
+reformat bibliography
+.It Xr bit 1
+calculator
+.It Xr bri 1
+backlight brightness control
+.It Xr c 1
+run C statements
+.It Xr dtch 1
+detached sessions
+.It Xr ever 1
+watch files
+.It Xr fbatt 1
+framebuffer battery indicator
+.It Xr fbclock 1
+framebuffer clock
+.It Xr glitch 1
+PNG glitcher
+.It Xr hi 1
+syntax highlighter
+.It Xr hnel 1
+PTY input remapper
+.It Xr modem 1
+fixed baud rate wrapper
+.It Xr nudge 1
+terminal vibrator
+.It Xr order 1
+operator precedence
+.It Xr pbd 1
+macOS pasteboard daemon
+.It Xr pngo 1
+PNG optimizer
+.It Xr psf2png 1
+PSF2 to PNG renderer
+.It Xr psfed 1
+PSF2 font editor
+.It Xr ptee 1
+tee for PTYs
+.It Xr relay 1
+IRC relay bot
+.It Xr scheme 1
+color scheme
+.It Xr shotty 1
+terminal capture
+.It Xr title 1
+page titles
+.It Xr ttpre 1
+man output to HTML
+.It Xr up 1
+upload file
+.It Xr when 1
+date calculator
+.It Xr xx 1
+hexdump
+.El
+.
+.Pp
+One piece of reused code.
+.Pp
+.Bl -tag -width "png(3)" -compact
+.It Xr png 3
+basic PNG output
+.El
diff --git a/bin/beef.c b/bin/beef.c
new file mode 100644
index 00000000..b2579b73
--- /dev/null
+++ b/bin/beef.c
@@ -0,0 +1,141 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <time.h>
+
+enum {
+	Cols = 80,
+	Rows = 25,
+};
+static char page[Rows][Cols];
+
+static char get(int y, int x) {
+	if (y < 0 || y >= Rows) return 0;
+	if (x < 0 || x >= Cols) return 0;
+	return page[y][x];
+}
+static void put(int y, int x, char v) {
+	if (y < 0 || y >= Rows) return;
+	if (x < 0 || x >= Cols) return;
+	page[y][x] = v;
+}
+
+enum { StackLen = 1024 };
+static long stack[StackLen];
+static size_t top = StackLen;
+
+static void push(long val) {
+	if (!top) errx(EX_SOFTWARE, "stack overflow");
+	stack[--top] = val;
+}
+static long pop(void) {
+	if (top == StackLen) return 0;
+	return stack[top++];
+}
+
+static struct {
+	int y, x;
+	int dy, dx;
+} pc = { .dx = 1 };
+
+static void inc(void) {
+	pc.y += pc.dy;
+	pc.x += pc.dx;
+	if (pc.y == -1) pc.y += Rows;
+	if (pc.x == -1) pc.x += Cols;
+	if (pc.y == Rows) pc.y -= Rows;
+	if (pc.x == Cols) pc.x -= Cols;
+}
+
+static bool string;
+
+static bool step(void) {
+	char ch = page[pc.y][pc.x];
+
+	if (ch == '"') {
+		string ^= true;
+	} else if (string) {
+		push(ch);
+		inc();
+		return true;
+	}
+
+	if (ch == '?') ch = "><^v"[rand() % 4];
+
+	long x, y, v;
+	switch (ch) {
+		break; case '+': push(pop() + pop());
+		break; case '-': y = pop(); x = pop(); push(x - y);
+		break; case '*': push(pop() * pop());
+		break; case '/': y = pop(); x = pop(); push(x / y);
+		break; case '%': y = pop(); x = pop(); push(x % y);
+		break; case '!': push(!pop());
+		break; case '`': y = pop(); x = pop(); push(x > y);
+		break; case '>': pc.dy = 0; pc.dx = +1;
+		break; case '<': pc.dy = 0; pc.dx = -1;
+		break; case '^': pc.dy = -1; pc.dx = 0;
+		break; case 'v': pc.dy = +1; pc.dx = 0;
+		break; case '_': pc.dy = 0; pc.dx = (pop() ? -1 : +1);
+		break; case '|': pc.dx = 0; pc.dy = (pop() ? -1 : +1);
+		break; case ':': x = pop(); push(x); push(x);
+		break; case '\\': y = pop(); x = pop(); push(y); push(x);
+		break; case '$': pop();
+		break; case '.': printf("%ld ", pop()); fflush(stdout);
+		break; case ',': printf("%c", (char)pop()); fflush(stdout);
+		break; case '#': inc();
+		break; case 'g': y = pop(); x = pop(); push(get(y, x));
+		break; case 'p': y = pop(); x = pop(); v = pop(); put(y, x, v);
+		break; case '&': x = EOF; scanf("%ld", &x); push(x);
+		break; case '~': push(getchar());
+		break; case '@': return false;
+		break; default:  if (ch >= '0' && ch <= '9') push(ch - '0');
+	}
+
+	inc();
+	return true;
+}
+
+int main(int argc, char *argv[]) {
+	srand(time(NULL));
+	memset(page, ' ', sizeof(page));
+
+	FILE *file = stdin;
+	if (argc > 1) {
+		file = fopen(argv[1], "r");
+		if (!file) err(EX_NOINPUT, "%s", argv[1]);
+	}
+
+	int y = 0;
+	char *line = NULL;
+	size_t cap = 0;
+	while (y < Rows && 0 < getline(&line, &cap, file)) {
+		for (int x = 0; x < Cols; ++x) {
+			if (line[x] == '\n' || !line[x]) break;
+			page[y][x] = line[x];
+		}
+		y++;
+	}
+	free(line);
+
+	while (step());
+	return pop();
+}
diff --git a/bin/bibsort.pl b/bin/bibsort.pl
new file mode 100644
index 00000000..f87f066f
--- /dev/null
+++ b/bin/bibsort.pl
@@ -0,0 +1,66 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+while (<>) {
+	print;
+	last if /^[.]Sh STANDARDS$/;
+}
+
+my ($ref, @refs);
+while (<>) {
+	next if /^[.](Bl|It|$)/;
+	last if /^[.]El$/;
+	if (/^[.]Rs$/) {
+		$ref = {};
+	} elsif (/^[.]%(.) (.*)/) {
+		$ref->{$1} = [] unless $ref->{$1};
+		push @{$ref->{$1}}, $2;
+	} elsif (/^[.]Re$/) {
+		push @refs, $ref;
+	} else {
+		print;
+	}
+}
+
+sub byLast {
+	my ($af, $al) = split /\s(\S+)(,.*)?$/, $a;
+	my ($bf, $bl) = split /\s(\S+)(,.*)?$/, $b;
+	$al cmp $bl || $af cmp $bf;
+}
+
+foreach $ref (@refs) {
+	@{$ref->{A}} = sort byLast @{$ref->{A}};
+	@{$ref->{Q}} = sort @{$ref->{Q}} if $ref->{Q};
+	next unless $ref->{N};
+	if ($ref->{N}[0] =~ /RFC/) {
+		$ref->{R} = $ref->{N};
+		delete $ref->{N};
+	}
+}
+
+sub byAuthor {
+	local ($a, $b) = ($a->{A}[0], $b->{A}[0]);
+	byLast();
+}
+
+{
+	local ($,, $\) = (' ', "\n");
+	print '.Bl', '-item';
+	foreach $ref (sort byAuthor @refs) {
+		print '.It';
+		print '.Rs';
+		foreach my $key (qw(A T B I J R N V U P Q C D O)) {
+			next unless $ref->{$key};
+			foreach (@{$ref->{$key}}) {
+				print ".%${key}", $_;
+			}
+		}
+		print '.Re';
+	}
+	print '.El';
+}
+
+while (<>) {
+	print;
+}
diff --git a/bin/bit.y b/bin/bit.y
new file mode 100644
index 00000000..0a9bc7ce
--- /dev/null
+++ b/bin/bit.y
@@ -0,0 +1,194 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+%{
+
+#include <ctype.h>
+#include <err.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+
+#define MASK(b) ((1ULL << (b)) - 1)
+
+static void yyerror(const char *str);
+static int yylex(void);
+
+#define YYSTYPE uint64_t
+
+static uint64_t vars[128];
+
+%}
+
+%right '='
+%left '|'
+%left '^'
+%left '&'
+%left Shl Shr Sar
+%left '+' '-'
+%left '*' '/' '%'
+%right '~'
+%left 'K' 'M' 'G' 'T'
+
+%token Int Var
+
+%%
+
+stmt:
+	expr { vars['_'] = $1; }
+	;
+
+expr:
+	Int
+	| Var { $$ = vars[$1]; }
+	| '(' expr ')' { $$ = $2; }
+	| expr 'K' { $$ = $1 << 10; }
+	| expr 'M' { $$ = $1 << 20; }
+	| expr 'G' { $$ = $1 << 30; }
+	| expr 'T' { $$ = $1 << 40; }
+	| '~' expr { $$ = ~$2; }
+	| '-' expr { $$ = -$2; }
+	| expr '*' expr { $$ = $1 * $3; }
+	| expr '/' expr { $$ = $1 / $3; }
+	| expr '%' expr { $$ = $1 % $3; }
+	| expr '+' expr { $$ = $1 + $3; }
+	| expr '-' expr { $$ = $1 - $3; }
+	| expr Shl expr { $$ = $1 << $3; }
+	| expr Shr expr { $$ = $1 >> $3; }
+	| expr Sar expr { $$ = (int64_t)$1 >> $3; }
+	| expr '&' expr { $$ = $1 & $3; }
+	| expr '^' expr { $$ = $1 ^ $3; }
+	| expr '|' expr { $$ = $1 | $3; }
+	| Var '=' expr { $$ = vars[$1] = $3; }
+	;
+
+%%
+
+static void yyerror(const char *str) {
+	warnx("%s", str);
+}
+
+#define T(a, b) ((int)(a) << 8 | (int)(b))
+
+static const char *input;
+
+static int lexInt(uint64_t base) {
+	for (yylval = 0; input[0]; ++input) {
+		uint64_t digit;
+		if (input[0] == '_') {
+			continue;
+		} else if (input[0] >= '0' && input[0] <= '9') {
+			digit = input[0] - '0';
+		} else if (input[0] >= 'A' && input[0] <= 'F') {
+			digit = 0xA + input[0] - 'A';
+		} else if (input[0] >= 'a' && input[0] <= 'f') {
+			digit = 0xA + input[0] - 'a';
+		} else {
+			return Int;
+		}
+		if (digit >= base) return Int;
+		yylval *= base;
+		yylval += digit;
+	}
+	return Int;
+}
+
+static int yylex(void) {
+	while (isspace(input[0])) input++;
+	if (!input[0]) return EOF;
+
+	if (input[0] == '\'' && input[1] && input[2] == '\'') {
+		yylval = input[1];
+		input += 3;
+		return Int;
+	}
+
+	if (input[0] == '0') {
+		if (input[1] == 'b') {
+			input += 2;
+			return lexInt(2);
+		} else if (input[1] == 'x') {
+			input += 2;
+			return lexInt(16);
+		} else {
+			input += 1;
+			return lexInt(8);
+		}
+	} else if (isdigit(input[0])) {
+		return lexInt(10);
+	}
+	
+	if (input[0] == '_' || islower(input[0])) {
+		yylval = *input++;
+		return Var;
+	}
+
+	switch (T(input[0], input[1])) {
+		case T('<', '<'): input += 2; return Shl;
+		case T('>', '>'): input += 2; return Shr;
+		case T('-', '>'): input += 2; return Sar;
+		default: return *input++;
+	}
+}
+
+int main(void) {
+	char *line = NULL;
+	size_t cap = 0;
+	while (0 < getline(&line, &cap, stdin)) {
+		if (line[0] == '\n') continue;
+
+		input = line;
+		int error = yyparse();
+		if (error) continue;
+
+		uint64_t result = vars['_'];
+
+		int bits = result > UINT32_MAX ? 64
+			: result > UINT16_MAX ? 32
+			: result > UINT8_MAX ? 16
+			: 8;
+
+		printf("0x%0*"PRIX64" %"PRId64"", bits >> 2, result, (int64_t)result);
+
+		if (bits == 8) {
+			char bin[9] = {0};
+			for (int i = 0; i < 8; ++i) {
+				bin[i] = '0' + (result >> (7 - i) & 1);
+			}
+			printf(" 0b%s", bin);
+		}
+
+		if (result < 128 && isprint(result)) {
+			printf(" '%c'", (char)result);
+		}
+
+		if (result) {
+			if (!(result & MASK(40))) {
+				printf(" %"PRIu64"T", result >> 40);
+			} else if (!(result & MASK(30))) {
+				printf(" %"PRIu64"G", result >> 30);
+			} else if (!(result & MASK(20))) {
+				printf(" %"PRIu64"M", result >> 20);
+			} else if (!(result & MASK(10))) {
+				printf(" %"PRIu64"K", result >> 10);
+			}
+		}
+
+		printf("\n\n");
+	}
+}
diff --git a/bin/bri.c b/bin/bri.c
new file mode 100644
index 00000000..81df2995
--- /dev/null
+++ b/bin/bri.c
@@ -0,0 +1,85 @@
+/* Copyright (C) 2017  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <dirent.h>
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+typedef unsigned uint;
+
+static const char *Class = "/sys/class/backlight";
+
+int main(int argc, char *argv[]) {
+	int error;
+
+	const char *input = (argc > 1) ? argv[1] : NULL;
+
+	error = chdir(Class);
+	if (error) err(EX_OSFILE, "%s", Class);
+
+	DIR *dir = opendir(".");
+	if (!dir) err(EX_OSFILE, "%s", Class);
+
+	struct dirent *entry;
+	while (NULL != (errno = 0, entry = readdir(dir))) {
+		if (entry->d_name[0] == '.') continue;
+
+		error = chdir(entry->d_name);
+		if (error) err(EX_OSFILE, "%s/%s", Class, entry->d_name);
+		break;
+	}
+	if (!entry) {
+		if (errno) err(EX_IOERR, "%s", Class);
+		errx(EX_CONFIG, "%s: empty", Class);
+	}
+
+	FILE *actual = fopen("actual_brightness", "r");
+	if (!actual) err(EX_OSFILE, "actual_brightness");
+
+	uint value;
+	int match = fscanf(actual, "%u", &value);
+	if (match == EOF) err(EX_IOERR, "actual_brightness");
+	if (match < 1) errx(EX_DATAERR, "actual_brightness");
+
+	if (!input) {
+		printf("%u\n", value);
+		return EX_OK;
+	}
+
+	if (input[0] == '+' || input[0] == '-') {
+		size_t count = strnlen(input, 16);
+		if (input[0] == '+') {
+			value += 16 * count;
+		} else {
+			value -= 16 * count;
+		}
+	} else {
+		value = strtoul(input, NULL, 0);
+	}
+
+	FILE *brightness = fopen("brightness", "w");
+	if (!brightness) err(EX_OSFILE, "brightness");
+
+	int size = fprintf(brightness, "%u", value);
+	if (size < 0) err(EX_IOERR, "brightness");
+
+	return EX_OK;
+}
diff --git a/bin/c.sh b/bin/c.sh
new file mode 100644
index 00000000..f1143fd3
--- /dev/null
+++ b/bin/c.sh
@@ -0,0 +1,87 @@
+#!/bin/sh
+set -eu
+
+temp=$(mktemp -d)
+trap 'rm -r "${temp}"' EXIT
+
+exec 3>>"${temp}/run.c"
+
+cat >&3 <<EOF
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include <fcntl.h>
+#include <strings.h>
+#include <unistd.h>
+EOF
+
+expr=
+while getopts 'e:i:' opt; do
+	case "${opt}" in
+		(e) expr=$OPTARG;;
+		(i) echo "#include <${OPTARG}>" >&3;;
+		(?) exit 1;;
+	esac
+done
+shift $((OPTIND - 1))
+
+cat >&3 <<EOF
+int main(int argc, char *argv[]) {
+	(void)argc;
+	(void)argv;
+	$*;
+EOF
+
+if [ -n "${expr}" ]; then
+	cat >&3 <<EOF
+	printf(
+		_Generic(
+			${expr},
+			char: "%c\n",
+			char *: "%s\n",
+			const char *: "%s\n",
+			wchar_t *: "%ls\n",
+			const wchar_t *: "%ls\n",
+			signed char: "%hhd\n",
+			short: "%hd\n",
+			int: "%d\n",
+			long: "%ld\n",
+			long long: "%lld\n",
+			unsigned char: "%hhu\n",
+			unsigned short: "%hu\n",
+			unsigned int: "%u\n",
+			unsigned long: "%lu\n",
+			unsigned long long: "%llu\n",
+			double: "%g\n",
+			default: "%p\n"
+		),
+		${expr}
+	);
+EOF
+fi
+
+if [ $# -eq 0 -a -z "${expr}" ]; then
+	cat >&3
+fi
+
+echo '}' >&3
+
+cat >"${temp}/Makefile" <<EOF
+CFLAGS += -Wall -Wextra -Wpedantic
+EOF
+
+make -s -C "${temp}" run
+"${temp}/run"
diff --git a/bin/dash/.gitignore b/bin/dash/.gitignore
new file mode 100644
index 00000000..e349901a
--- /dev/null
+++ b/bin/dash/.gitignore
@@ -0,0 +1,42 @@
+# .gitignore for dash
+
+# generated by autogen.sh
+Makefile.in
+/aclocal.m4
+/autom4te.cache/
+/compile
+/config.h.in
+/configure
+/depcomp
+/install-sh
+/missing
+
+# generated by configure
+Makefile
+.deps
+.dirstamp
+/config.cache
+/config.h
+/config.log
+/config.status
+/stamp-h1
+
+# generated by make
+/src/token_vars.h
+
+# Apple debug symbol bundles
+*.dSYM/
+
+# backups and patch artefacts
+*~
+*.bak
+*.orig
+*.rej
+
+# OS generated files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight*
+.Trash*
+*[Tt]humbs.db
diff --git a/COPYING b/bin/dash/COPYING
index 37f8189c..37f8189c 100644
--- a/COPYING
+++ b/bin/dash/COPYING
diff --git a/ChangeLog b/bin/dash/ChangeLog
index 406e20c0..406e20c0 100644
--- a/ChangeLog
+++ b/bin/dash/ChangeLog
diff --git a/ChangeLog.O b/bin/dash/ChangeLog.O
index dfdb2cec..dfdb2cec 100644
--- a/ChangeLog.O
+++ b/bin/dash/ChangeLog.O
diff --git a/Makefile.am b/bin/dash/Makefile.am
index af437a64..af437a64 100644
--- a/Makefile.am
+++ b/bin/dash/Makefile.am
diff --git a/autogen.sh b/bin/dash/autogen.sh
index 9879c53e..9879c53e 100755
--- a/autogen.sh
+++ b/bin/dash/autogen.sh
diff --git a/configure.ac b/bin/dash/configure.ac
index 33f0b08c..33f0b08c 100644
--- a/configure.ac
+++ b/bin/dash/configure.ac
diff --git a/src/.gitignore b/bin/dash/src/.gitignore
index 644eccb8..644eccb8 100644
--- a/src/.gitignore
+++ b/bin/dash/src/.gitignore
diff --git a/src/Makefile.am b/bin/dash/src/Makefile.am
index 17324653..17324653 100644
--- a/src/Makefile.am
+++ b/bin/dash/src/Makefile.am
diff --git a/src/TOUR b/bin/dash/src/TOUR
index e30836e1..e30836e1 100644
--- a/src/TOUR
+++ b/bin/dash/src/TOUR
diff --git a/src/alias.c b/bin/dash/src/alias.c
index daeacbb8..daeacbb8 100644
--- a/src/alias.c
+++ b/bin/dash/src/alias.c
diff --git a/src/alias.h b/bin/dash/src/alias.h
index fb841d64..fb841d64 100644
--- a/src/alias.h
+++ b/bin/dash/src/alias.h
diff --git a/src/arith_yacc.c b/bin/dash/src/arith_yacc.c
index 1a087c32..1a087c32 100644
--- a/src/arith_yacc.c
+++ b/bin/dash/src/arith_yacc.c
diff --git a/src/arith_yacc.h b/bin/dash/src/arith_yacc.h
index ff34d524..ff34d524 100644
--- a/src/arith_yacc.h
+++ b/bin/dash/src/arith_yacc.h
diff --git a/src/arith_yylex.c b/bin/dash/src/arith_yylex.c
index ec5b5b25..ec5b5b25 100644
--- a/src/arith_yylex.c
+++ b/bin/dash/src/arith_yylex.c
diff --git a/src/bltin/bltin.h b/bin/dash/src/bltin/bltin.h
index f5ac06f2..f5ac06f2 100644
--- a/src/bltin/bltin.h
+++ b/bin/dash/src/bltin/bltin.h
diff --git a/src/bltin/echo.1 b/bin/dash/src/bltin/echo.1
index fbc7fb43..fbc7fb43 100644
--- a/src/bltin/echo.1
+++ b/bin/dash/src/bltin/echo.1
diff --git a/src/bltin/printf.1 b/bin/dash/src/bltin/printf.1
index 38731732..38731732 100644
--- a/src/bltin/printf.1
+++ b/bin/dash/src/bltin/printf.1
diff --git a/src/bltin/printf.c b/bin/dash/src/bltin/printf.c
index 7785735b..7785735b 100644
--- a/src/bltin/printf.c
+++ b/bin/dash/src/bltin/printf.c
diff --git a/src/bltin/test.1 b/bin/dash/src/bltin/test.1
index 42435fb3..42435fb3 100644
--- a/src/bltin/test.1
+++ b/bin/dash/src/bltin/test.1
diff --git a/src/bltin/test.c b/bin/dash/src/bltin/test.c
index c7fc479d..c7fc479d 100644
--- a/src/bltin/test.c
+++ b/bin/dash/src/bltin/test.c
diff --git a/src/bltin/times.c b/bin/dash/src/bltin/times.c
index 1166a68e..1166a68e 100644
--- a/src/bltin/times.c
+++ b/bin/dash/src/bltin/times.c
diff --git a/src/builtins.def.in b/bin/dash/src/builtins.def.in
index 95e420cc..95e420cc 100644
--- a/src/builtins.def.in
+++ b/bin/dash/src/builtins.def.in
diff --git a/src/cd.c b/bin/dash/src/cd.c
index 1ef1dc56..1ef1dc56 100644
--- a/src/cd.c
+++ b/bin/dash/src/cd.c
diff --git a/src/cd.h b/bin/dash/src/cd.h
index 87631619..87631619 100644
--- a/src/cd.h
+++ b/bin/dash/src/cd.h
diff --git a/src/dash.1 b/bin/dash/src/dash.1
index 32f6ac0d..32f6ac0d 100644
--- a/src/dash.1
+++ b/bin/dash/src/dash.1
diff --git a/src/error.c b/bin/dash/src/error.c
index 728ff885..728ff885 100644
--- a/src/error.c
+++ b/bin/dash/src/error.c
diff --git a/src/error.h b/bin/dash/src/error.h
index 94e30a27..94e30a27 100644
--- a/src/error.h
+++ b/bin/dash/src/error.h
diff --git a/src/eval.c b/bin/dash/src/eval.c
index 1b5d61dc..1b5d61dc 100644
--- a/src/eval.c
+++ b/bin/dash/src/eval.c
diff --git a/src/eval.h b/bin/dash/src/eval.h
index 63e7d865..63e7d865 100644
--- a/src/eval.h
+++ b/bin/dash/src/eval.h
diff --git a/src/exec.c b/bin/dash/src/exec.c
index 87354d49..87354d49 100644
--- a/src/exec.c
+++ b/bin/dash/src/exec.c
diff --git a/src/exec.h b/bin/dash/src/exec.h
index 423b07e6..423b07e6 100644
--- a/src/exec.h
+++ b/bin/dash/src/exec.h
diff --git a/src/expand.c b/bin/dash/src/expand.c
index 1730670e..1730670e 100644
--- a/src/expand.c
+++ b/bin/dash/src/expand.c
diff --git a/src/expand.h b/bin/dash/src/expand.h
index c44b8481..c44b8481 100644
--- a/src/expand.h
+++ b/bin/dash/src/expand.h
diff --git a/src/funcs/cmv b/bin/dash/src/funcs/cmv
index 91a67c53..91a67c53 100644
--- a/src/funcs/cmv
+++ b/bin/dash/src/funcs/cmv
diff --git a/src/funcs/dirs b/bin/dash/src/funcs/dirs
index 5f6ce635..5f6ce635 100644
--- a/src/funcs/dirs
+++ b/bin/dash/src/funcs/dirs
diff --git a/src/funcs/kill b/bin/dash/src/funcs/kill
index c5df95f5..c5df95f5 100644
--- a/src/funcs/kill
+++ b/bin/dash/src/funcs/kill
diff --git a/src/funcs/login b/bin/dash/src/funcs/login
index 215e5352..215e5352 100644
--- a/src/funcs/login
+++ b/bin/dash/src/funcs/login
diff --git a/src/funcs/newgrp b/bin/dash/src/funcs/newgrp
index ec0e7e5a..ec0e7e5a 100644
--- a/src/funcs/newgrp
+++ b/bin/dash/src/funcs/newgrp
diff --git a/src/funcs/popd b/bin/dash/src/funcs/popd
index 7bccf50d..7bccf50d 100644
--- a/src/funcs/popd
+++ b/bin/dash/src/funcs/popd
diff --git a/src/funcs/pushd b/bin/dash/src/funcs/pushd
index 19ac8e08..19ac8e08 100644
--- a/src/funcs/pushd
+++ b/bin/dash/src/funcs/pushd
diff --git a/src/funcs/suspend b/bin/dash/src/funcs/suspend
index 44844678..44844678 100644
--- a/src/funcs/suspend
+++ b/bin/dash/src/funcs/suspend
diff --git a/src/histedit.c b/bin/dash/src/histedit.c
index f5c90aba..f5c90aba 100644
--- a/src/histedit.c
+++ b/bin/dash/src/histedit.c
diff --git a/src/init.h b/bin/dash/src/init.h
index d56fb28e..d56fb28e 100644
--- a/src/init.h
+++ b/bin/dash/src/init.h
diff --git a/src/input.c b/bin/dash/src/input.c
index 17544e78..17544e78 100644
--- a/src/input.c
+++ b/bin/dash/src/input.c
diff --git a/src/input.h b/bin/dash/src/input.h
index 8acc6e9f..8acc6e9f 100644
--- a/src/input.h
+++ b/bin/dash/src/input.h
diff --git a/src/jobs.c b/bin/dash/src/jobs.c
index d4c13c0f..d4c13c0f 100644
--- a/src/jobs.c
+++ b/bin/dash/src/jobs.c
diff --git a/src/jobs.h b/bin/dash/src/jobs.h
index 6ac6c56d..6ac6c56d 100644
--- a/src/jobs.h
+++ b/bin/dash/src/jobs.h
diff --git a/src/machdep.h b/bin/dash/src/machdep.h
index f2ff0ad8..f2ff0ad8 100644
--- a/src/machdep.h
+++ b/bin/dash/src/machdep.h
diff --git a/src/mail.c b/bin/dash/src/mail.c
index 8eacb2d0..8eacb2d0 100644
--- a/src/mail.c
+++ b/bin/dash/src/mail.c
diff --git a/src/mail.h b/bin/dash/src/mail.h
index 3c6b21d2..3c6b21d2 100644
--- a/src/mail.h
+++ b/bin/dash/src/mail.h
diff --git a/src/main.c b/bin/dash/src/main.c
index 7a285346..7a285346 100644
--- a/src/main.c
+++ b/bin/dash/src/main.c
diff --git a/src/main.h b/bin/dash/src/main.h
index 19e49835..19e49835 100644
--- a/src/main.h
+++ b/bin/dash/src/main.h
diff --git a/src/memalloc.c b/bin/dash/src/memalloc.c
index 60637da1..60637da1 100644
--- a/src/memalloc.c
+++ b/bin/dash/src/memalloc.c
diff --git a/src/memalloc.h b/bin/dash/src/memalloc.h
index b9adf764..b9adf764 100644
--- a/src/memalloc.h
+++ b/bin/dash/src/memalloc.h
diff --git a/src/miscbltin.c b/bin/dash/src/miscbltin.c
index 5ccbbcb8..5ccbbcb8 100644
--- a/src/miscbltin.c
+++ b/bin/dash/src/miscbltin.c
diff --git a/src/miscbltin.h b/bin/dash/src/miscbltin.h
index dd9a8d1c..dd9a8d1c 100644
--- a/src/miscbltin.h
+++ b/bin/dash/src/miscbltin.h
diff --git a/src/mkbuiltins b/bin/dash/src/mkbuiltins
index f1f25932..f1f25932 100644
--- a/src/mkbuiltins
+++ b/bin/dash/src/mkbuiltins
diff --git a/src/mkinit.c b/bin/dash/src/mkinit.c
index 9025862e..9025862e 100644
--- a/src/mkinit.c
+++ b/bin/dash/src/mkinit.c
diff --git a/src/mknodes.c b/bin/dash/src/mknodes.c
index 1903a605..1903a605 100644
--- a/src/mknodes.c
+++ b/bin/dash/src/mknodes.c
diff --git a/src/mksignames.c b/bin/dash/src/mksignames.c
index a832eab9..a832eab9 100644
--- a/src/mksignames.c
+++ b/bin/dash/src/mksignames.c
diff --git a/src/mksyntax.c b/bin/dash/src/mksyntax.c
index a23c18ca..a23c18ca 100644
--- a/src/mksyntax.c
+++ b/bin/dash/src/mksyntax.c
diff --git a/src/mktokens b/bin/dash/src/mktokens
index 78055be8..78055be8 100644
--- a/src/mktokens
+++ b/bin/dash/src/mktokens
diff --git a/src/myhistedit.h b/bin/dash/src/myhistedit.h
index 22e5c438..22e5c438 100644
--- a/src/myhistedit.h
+++ b/bin/dash/src/myhistedit.h
diff --git a/src/mystring.c b/bin/dash/src/mystring.c
index de624b89..de624b89 100644
--- a/src/mystring.c
+++ b/bin/dash/src/mystring.c
diff --git a/src/mystring.h b/bin/dash/src/mystring.h
index 083ea98c..083ea98c 100644
--- a/src/mystring.h
+++ b/bin/dash/src/mystring.h
diff --git a/src/nodes.c.pat b/bin/dash/src/nodes.c.pat
index 9125bc73..9125bc73 100644
--- a/src/nodes.c.pat
+++ b/bin/dash/src/nodes.c.pat
diff --git a/src/nodetypes b/bin/dash/src/nodetypes
index ceaf478c..ceaf478c 100644
--- a/src/nodetypes
+++ b/bin/dash/src/nodetypes
diff --git a/src/options.c b/bin/dash/src/options.c
index a46c23b9..a46c23b9 100644
--- a/src/options.c
+++ b/bin/dash/src/options.c
diff --git a/src/options.h b/bin/dash/src/options.h
index 975fe339..975fe339 100644
--- a/src/options.h
+++ b/bin/dash/src/options.h
diff --git a/src/output.c b/bin/dash/src/output.c
index e9ee9b4d..e9ee9b4d 100644
--- a/src/output.c
+++ b/bin/dash/src/output.c
diff --git a/src/output.h b/bin/dash/src/output.h
index c43d4937..c43d4937 100644
--- a/src/output.h
+++ b/bin/dash/src/output.h
diff --git a/src/parser.c b/bin/dash/src/parser.c
index a47022e0..a47022e0 100644
--- a/src/parser.c
+++ b/bin/dash/src/parser.c
diff --git a/src/parser.h b/bin/dash/src/parser.h
index 524ac1c7..524ac1c7 100644
--- a/src/parser.h
+++ b/bin/dash/src/parser.h
diff --git a/src/redir.c b/bin/dash/src/redir.c
index 895140c3..895140c3 100644
--- a/src/redir.c
+++ b/bin/dash/src/redir.c
diff --git a/src/redir.h b/bin/dash/src/redir.h
index 1cf27616..1cf27616 100644
--- a/src/redir.h
+++ b/bin/dash/src/redir.h
diff --git a/src/shell.h b/bin/dash/src/shell.h
index 98edc8be..98edc8be 100644
--- a/src/shell.h
+++ b/bin/dash/src/shell.h
diff --git a/src/show.c b/bin/dash/src/show.c
index 4a049e93..4a049e93 100644
--- a/src/show.c
+++ b/bin/dash/src/show.c
diff --git a/src/show.h b/bin/dash/src/show.h
index d0ccac79..d0ccac79 100644
--- a/src/show.h
+++ b/bin/dash/src/show.h
diff --git a/src/system.c b/bin/dash/src/system.c
index 844a6410..844a6410 100644
--- a/src/system.c
+++ b/bin/dash/src/system.c
diff --git a/src/system.h b/bin/dash/src/system.h
index 007952c5..007952c5 100644
--- a/src/system.h
+++ b/bin/dash/src/system.h
diff --git a/src/trap.c b/bin/dash/src/trap.c
index cd84814f..cd84814f 100644
--- a/src/trap.c
+++ b/bin/dash/src/trap.c
diff --git a/src/trap.h b/bin/dash/src/trap.h
index beaf6605..beaf6605 100644
--- a/src/trap.h
+++ b/bin/dash/src/trap.h
diff --git a/src/var.c b/bin/dash/src/var.c
index ef9c2bde..ef9c2bde 100644
--- a/src/var.c
+++ b/bin/dash/src/var.c
diff --git a/src/var.h b/bin/dash/src/var.h
index aa7575a7..aa7575a7 100644
--- a/src/var.h
+++ b/bin/dash/src/var.h
diff --git a/bin/dtch.c b/bin/dtch.c
new file mode 100644
index 00000000..2aea53ae
--- /dev/null
+++ b/bin/dtch.c
@@ -0,0 +1,271 @@
+/* Copyright (C) 2017-2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+
+#if defined __FreeBSD__
+#include <libutil.h>
+#elif defined __linux__
+#include <pty.h>
+#else
+#include <util.h>
+#endif
+
+static char _;
+static struct iovec iov = { .iov_base = &_, .iov_len = 1 };
+
+static ssize_t sendfd(int sock, int fd) {
+	size_t len = CMSG_SPACE(sizeof(int));
+	char buf[len];
+	struct msghdr msg = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = buf,
+		.msg_controllen = len,
+	};
+
+	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	*(int *)CMSG_DATA(cmsg) = fd;
+
+	return sendmsg(sock, &msg, 0);
+}
+
+static int recvfd(int sock) {
+	size_t len = CMSG_SPACE(sizeof(int));
+	char buf[len];
+	struct msghdr msg = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = buf,
+		.msg_controllen = len,
+	};
+	if (0 > recvmsg(sock, &msg, 0)) return -1;
+
+	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+	if (!cmsg || cmsg->cmsg_type != SCM_RIGHTS) {
+		errno = ENOMSG;
+		return -1;
+	}
+	return *(int *)CMSG_DATA(cmsg);
+}
+
+static struct sockaddr_un addr = { .sun_family = AF_UNIX };
+
+static void handler(int sig) {
+	unlink(addr.sun_path);
+	_exit(-sig);
+}
+
+static void detach(int server, bool sink, char *argv[]) {
+	int pty;
+	pid_t pid = forkpty(&pty, NULL, NULL, NULL);
+	if (pid < 0) err(EX_OSERR, "forkpty");
+
+	if (!pid) {
+		execvp(argv[0], argv);
+		err(EX_NOINPUT, "%s", argv[0]);
+	}
+
+	signal(SIGINT, handler);
+	signal(SIGTERM, handler);
+
+	int error = listen(server, 0);
+	if (error) err(EX_OSERR, "listen");
+
+	struct pollfd fds[] = {
+		{ .events = POLLIN, .fd = server },
+		{ .events = POLLIN, .fd = pty },
+	};
+	while (0 < poll(fds, (sink ? 2 : 1), -1)) {
+		if (fds[0].revents) {
+			int client = accept(server, NULL, NULL);
+			if (client < 0) err(EX_IOERR, "accept");
+
+			ssize_t len = sendfd(client, pty);
+			if (len < 0) warn("sendfd");
+
+			len = recv(client, &_, sizeof(_), 0);
+			if (len < 0) warn("recv");
+
+			close(client);
+		}
+
+		if (fds[1].revents) {
+			char buf[4096];
+			ssize_t len = read(pty, buf, sizeof(buf));
+			if (len < 0) err(EX_IOERR, "read");
+		}
+
+		int status;
+		pid_t dead = waitpid(pid, &status, WNOHANG);
+		if (dead < 0) err(EX_OSERR, "waitpid");
+		if (dead) {
+			unlink(addr.sun_path);
+			exit(WIFEXITED(status) ? WEXITSTATUS(status) : -WTERMSIG(status));
+		}
+	}
+	err(EX_IOERR, "poll");
+}
+
+static struct termios saveTerm;
+static void restoreTerm(void) {
+	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
+	fprintf(stderr, "\33c"); // RIS
+	warnx("detached");
+}
+
+static void nop(int sig) {
+	(void)sig;
+}
+
+static void attach(int client) {
+	int error;
+
+	int pty = recvfd(client);
+	if (pty < 0) err(EX_IOERR, "recvfd");
+	warnx("attached");
+
+	struct winsize window;
+	error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window);
+	if (error) err(EX_IOERR, "ioctl");
+
+	struct winsize redraw = { .ws_row = 1, .ws_col = 1 };
+	error = ioctl(pty, TIOCSWINSZ, &redraw);
+	if (error) err(EX_IOERR, "ioctl");
+
+	error = ioctl(pty, TIOCSWINSZ, &window);
+	if (error) err(EX_IOERR, "ioctl");
+
+	error = tcgetattr(STDIN_FILENO, &saveTerm);
+	if (error) err(EX_IOERR, "tcgetattr");
+	atexit(restoreTerm);
+
+	struct termios raw = saveTerm;
+	cfmakeraw(&raw);
+	error = tcsetattr(STDIN_FILENO, TCSADRAIN, &raw);
+	if (error) err(EX_IOERR, "tcsetattr");
+
+	signal(SIGWINCH, nop);
+
+	char buf[4096];
+	struct pollfd fds[] = {
+		{ .events = POLLIN, .fd = STDIN_FILENO },
+		{ .events = POLLIN, .fd = pty },
+	};
+	for (;;) {
+		int nfds = poll(fds, 2, -1);
+		if (nfds < 0) {
+			if (errno != EINTR) err(EX_IOERR, "poll");
+
+			error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window);
+			if (error) err(EX_IOERR, "ioctl");
+
+			error = ioctl(pty, TIOCSWINSZ, &window);
+			if (error) err(EX_IOERR, "ioctl");
+
+			continue;
+		}
+
+		if (fds[0].revents) {
+			ssize_t len = read(STDIN_FILENO, buf, sizeof(buf));
+			if (len < 0) err(EX_IOERR, "read");
+			if (!len) break;
+
+			if (len == 1 && buf[0] == CTRL('Q')) break;
+
+			len = write(pty, buf, len);
+			if (len < 0) err(EX_IOERR, "write");
+		}
+
+		if (fds[1].revents) {
+			ssize_t len = read(pty, buf, sizeof(buf));
+			if (len < 0) err(EX_IOERR, "read");
+			if (!len) break;
+
+			len = write(STDOUT_FILENO, buf, len);
+			if (len < 0) err(EX_IOERR, "write");
+		}
+	}
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+
+	bool atch = false;
+	bool sink = false;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "as"))) {
+		switch (opt) {
+			break; case 'a': atch = true;
+			break; case 's': sink = true;
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (optind == argc) errx(EX_USAGE, "no session name");
+	const char *name = argv[optind++];
+
+	if (optind == argc) {
+		argv[--optind] = getenv("SHELL");
+		if (!argv[optind]) errx(EX_CONFIG, "SHELL unset");
+	}
+
+	const char *home = getenv("HOME");
+	if (!home) errx(EX_CONFIG, "HOME unset");
+
+	int fd = open(home, 0);
+	if (fd < 0) err(EX_CANTCREAT, "%s", home);
+
+	error = mkdirat(fd, ".dtch", 0700);
+	if (error && errno != EEXIST) err(EX_CANTCREAT, "%s/.dtch", home);
+
+	close(fd);
+
+	int sock = socket(PF_UNIX, SOCK_STREAM, 0);
+	if (sock < 0) err(EX_OSERR, "socket");
+	fcntl(sock, F_SETFD, FD_CLOEXEC);
+
+	snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/.dtch/%s", home, name);
+
+	if (atch) {
+		error = connect(sock, (struct sockaddr *)&addr, SUN_LEN(&addr));
+		if (error) err(EX_NOINPUT, "%s", addr.sun_path);
+		attach(sock);
+	} else {
+		error = bind(sock, (struct sockaddr *)&addr, SUN_LEN(&addr));
+		if (error) err(EX_CANTCREAT, "%s", addr.sun_path);
+		detach(sock, sink, &argv[optind]);
+	}
+}
diff --git a/bin/ever.c b/bin/ever.c
new file mode 100644
index 00000000..258b058b
--- /dev/null
+++ b/bin/ever.c
@@ -0,0 +1,116 @@
+/* Copyright (C) 2017  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <sys/event.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static int watch(int kq, char *path) {
+	int fd = open(path, O_CLOEXEC);
+	if (fd < 0) err(EX_NOINPUT, "%s", path);
+
+	struct kevent event;
+	EV_SET(
+		&event,
+		fd,
+		EVFILT_VNODE,
+		EV_ADD | EV_CLEAR,
+		NOTE_WRITE | NOTE_DELETE,
+		0,
+		path
+	);
+	int nevents = kevent(kq, &event, 1, NULL, 0, NULL);
+	if (nevents < 0) err(EX_OSERR, "kevent");
+
+	return fd;
+}
+
+static void exec(int fd, char *const argv[]) {
+	pid_t pid = fork();
+	if (pid < 0) err(EX_OSERR, "fork");
+
+	if (!pid) {
+		dup2(fd, STDIN_FILENO);
+		execvp(*argv, argv);
+		err(EX_NOINPUT, "%s", *argv);
+	}
+
+	int status;
+	pid = wait(&status);
+	if (pid < 0) err(EX_OSERR, "wait");
+
+	if (WIFEXITED(status)) {
+		warnx("exit %d\n", WEXITSTATUS(status));
+	} else if (WIFSIGNALED(status)) {
+		warnx("signal %d\n", WTERMSIG(status));
+	} else {
+		warnx("status %d\n", status);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	bool input = false;
+
+	for (int opt; 0 < (opt = getopt(argc, argv, "i"));) {
+		switch (opt) {
+			break; case 'i': input = true;
+			break; default:  return EX_USAGE;
+		}
+	}
+	argc -= optind;
+	argv += optind;
+	if (argc < 2) return EX_USAGE;
+
+	int kq = kqueue();
+	if (kq < 0) err(EX_OSERR, "kqueue");
+
+	int i;
+	for (i = 0; i < argc - 1; ++i) {
+		if (argv[i][0] == '-') {
+			i++;
+			break;
+		}
+		watch(kq, argv[i]);
+	}
+
+	if (!input) {
+		exec(STDIN_FILENO, &argv[i]);
+	}
+
+	for (;;) {
+		struct kevent event;
+		int nevents = kevent(kq, NULL, 0, &event, 1, NULL);
+		if (nevents < 0) err(EX_OSERR, "kevent");
+
+		if (event.fflags & NOTE_DELETE) {
+			close(event.ident);
+			sleep(1);
+			event.ident = watch(kq, (char *)event.udata);
+		} else if (input) {
+			off_t off = lseek(event.ident, 0, SEEK_SET);
+			if (off < 0) err(EX_IOERR, "lseek");
+		}
+
+		exec((input ? event.ident : STDIN_FILENO), &argv[i]);
+	}
+}
diff --git a/bin/fbatt.c b/bin/fbatt.c
new file mode 100644
index 00000000..9feffe47
--- /dev/null
+++ b/bin/fbatt.c
@@ -0,0 +1,123 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <dirent.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+#include "scheme.h"
+
+static const char *Class = "/sys/class/power_supply";
+
+static const uint32_t Right  = 5 * 8 + 1; // fbclock width.
+static const uint32_t Width  = 8;
+static const uint32_t Height = 16;
+
+int main() {
+	int error;
+
+	DIR *dir = opendir(Class);
+	if (!dir) err(EX_OSFILE, "%s", Class);
+
+	FILE *chargeFull = NULL;
+	FILE *chargeNow = NULL;
+
+	const struct dirent *entry;
+	while (NULL != (errno = 0, entry = readdir(dir))) {
+		if (entry->d_name[0] == '.') continue;
+
+		error = chdir(Class);
+		if (error) err(EX_OSFILE, "%s", Class);
+
+		error = chdir(entry->d_name);
+		if (error) err(EX_OSFILE, "%s/%s", Class, entry->d_name);
+
+		chargeFull = fopen("charge_full", "r");
+		chargeNow = fopen("charge_now", "r");
+		if (chargeFull && chargeNow) break;
+	}
+	if (!chargeFull || !chargeNow) {
+		if (errno) err(EX_OSFILE, "%s", Class);
+		errx(EX_CONFIG, "%s: empty", Class);
+	}
+	closedir(dir);
+
+	const char *path = getenv("FRAMEBUFFER");
+	if (!path) path = "/dev/fb0";
+
+	int fb = open(path, O_RDWR);
+	if (fb < 0) err(EX_OSFILE, "%s", path);
+
+	struct fb_var_screeninfo info;
+	error = ioctl(fb, FBIOGET_VSCREENINFO, &info);
+	if (error) err(EX_IOERR, "%s", path);
+
+	size_t size = 4 * info.xres * info.yres;
+	uint32_t *buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
+	if (buf == MAP_FAILED) err(EX_IOERR, "%s", path);
+
+	for (;;) {
+		int match;
+
+		rewind(chargeFull);
+		fflush(chargeFull);
+		uint32_t full;
+		match = fscanf(chargeFull, "%u", &full);
+		if (match == EOF) err(EX_IOERR, "charge_full");
+		if (match < 1) errx(EX_DATAERR, "charge_full");
+
+		rewind(chargeNow);
+		fflush(chargeNow);
+		uint32_t now;
+		match = fscanf(chargeNow, "%u", &now);
+		if (match == EOF) err(EX_IOERR, "charge_now");
+		if (match < 1) errx(EX_DATAERR, "charge_now");
+
+		uint32_t percent = 100 * now / full;
+		uint32_t height = 16 * now / full;
+
+		for (int i = 0; i < 60; ++i, sleep(1)) {
+			uint32_t left = info.xres - Right - Width;
+
+			for (uint32_t y = 0; y <= Height; ++y) {
+				buf[y * info.xres + left - 1] = DarkWhite;
+				buf[y * info.xres + left + Width] = DarkWhite;
+			}
+			for (uint32_t x = left; x < left + Width; ++x) {
+				buf[Height * info.xres + x] = DarkWhite;
+			}
+
+			for (uint32_t y = 0; y < Height; ++y) {
+				for (uint32_t x = left; x < left + Width; ++x) {
+					buf[y * info.xres + x] =
+						(Height - 1 - y > height) ? DarkBlack
+						: (percent <= 10) ? DarkRed
+						: (percent <= 30) ? DarkYellow
+						: LightBlack;
+				}
+			}
+		}
+	}
+}
diff --git a/bin/fbclock.c b/bin/fbclock.c
new file mode 100644
index 00000000..ddc32db6
--- /dev/null
+++ b/bin/fbclock.c
@@ -0,0 +1,132 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <err.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sysexits.h>
+#include <time.h>
+#include <unistd.h>
+#include <zlib.h>
+
+#include "scheme.h"
+
+static const uint32_t PSF2Magic = 0x864AB572;
+struct PSF2Header {
+	uint32_t magic;
+	uint32_t version;
+	uint32_t headerSize;
+	uint32_t flags;
+	uint32_t glyphCount;
+	uint32_t glyphSize;
+	uint32_t glyphHeight;
+	uint32_t glyphWidth;
+};
+
+int main() {
+	size_t len;
+
+	const char *fontPath = getenv("FONT");
+	if (!fontPath) {
+		fontPath = "/usr/share/kbd/consolefonts/Lat2-Terminus16.psfu.gz";
+	}
+
+	gzFile font = gzopen(fontPath, "r");
+	if (!font) err(EX_NOINPUT, "%s", fontPath);
+
+	struct PSF2Header header;
+	len = gzfread(&header, sizeof(header), 1, font);
+	if (!len && gzeof(font)) errx(EX_DATAERR, "%s: missing header", fontPath);
+	if (!len) errx(EX_IOERR, "%s", gzerror(font, NULL));
+
+	if (header.magic != PSF2Magic) {
+		errx(
+			EX_DATAERR, "%s: invalid header magic %08X",
+			fontPath, header.magic
+		);
+	}
+	if (header.headerSize != sizeof(struct PSF2Header)) {
+		errx(
+			EX_DATAERR, "%s: weird header size %d",
+			fontPath, header.headerSize
+		);
+	}
+
+	uint8_t glyphs[128][header.glyphSize];
+	len = gzfread(glyphs, header.glyphSize, 128, font);
+	if (!len && gzeof(font)) errx(EX_DATAERR, "%s: missing glyphs", fontPath);
+	if (!len) errx(EX_IOERR, "%s", gzerror(font, NULL));
+
+	gzclose(font);
+
+	const char *fbPath = getenv("FRAMEBUFFER");
+	if (!fbPath) fbPath = "/dev/fb0";
+
+	int fb = open(fbPath, O_RDWR);
+	if (fb < 0) err(EX_OSFILE, "%s", fbPath);
+
+	struct fb_var_screeninfo info;
+	int error = ioctl(fb, FBIOGET_VSCREENINFO, &info);
+	if (error) err(EX_IOERR, "%s", fbPath);
+
+	size_t size = 4 * info.xres * info.yres;
+	uint32_t *buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
+	if (buf == MAP_FAILED) err(EX_IOERR, "%s", fbPath);
+
+	for (;;) {
+		time_t t = time(NULL);
+		if (t < 0) err(EX_OSERR, "time");
+		const struct tm *local = localtime(&t);
+		if (!local) err(EX_OSERR, "localtime");
+
+		char str[64];
+		len = strftime(str, sizeof(str), "%H:%M", local);
+		assert(len);
+
+		for (int i = 0; i < (60 - local->tm_sec); ++i, sleep(1)) {
+			uint32_t left = info.xres - header.glyphWidth * len;
+			uint32_t bottom = header.glyphHeight;
+
+			for (uint32_t y = 0; y < bottom; ++y) {
+				buf[y * info.xres + left - 1] = DarkWhite;
+			}
+			for (uint32_t x = left - 1; x < info.xres; ++x) {
+				buf[bottom * info.xres + x] = DarkWhite;
+			}
+
+			for (const char *s = str; *s; ++s) {
+				const uint8_t *glyph = glyphs[(unsigned)*s];
+				uint32_t stride = header.glyphSize / header.glyphHeight;
+				for (uint32_t y = 0; y < header.glyphHeight; ++y) {
+					for (uint32_t x = 0; x < header.glyphWidth; ++x) {
+						uint8_t bits = glyph[y * stride + x / 8];
+						uint8_t bit = bits >> (7 - x % 8) & 1;
+						buf[y * info.xres + left + x] = bit
+							? DarkWhite
+							: DarkBlack;
+					}
+				}
+				left += header.glyphWidth;
+			}
+		}
+	}
+}
diff --git a/bin/glitch.c b/bin/glitch.c
new file mode 100644
index 00000000..9747f35a
--- /dev/null
+++ b/bin/glitch.c
@@ -0,0 +1,538 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <zlib.h>
+
+#define PACKED __attribute__((packed))
+
+#define CRC_INIT (crc32(0, Z_NULL, 0))
+
+static const char *path;
+static FILE *file;
+static uint32_t crc;
+
+static void readExpect(void *ptr, size_t size, const char *expect) {
+	fread(ptr, size, 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	if (feof(file)) errx(EX_DATAERR, "%s: missing %s", path, expect);
+	crc = crc32(crc, ptr, size);
+}
+
+static void writeExpect(const void *ptr, size_t size) {
+	fwrite(ptr, size, 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	crc = crc32(crc, ptr, size);
+}
+
+static const uint8_t Signature[8] = "\x89PNG\r\n\x1A\n";
+
+static void readSignature(void) {
+	uint8_t signature[8];
+	readExpect(signature, 8, "signature");
+	if (0 != memcmp(signature, Signature, 8)) {
+		errx(EX_DATAERR, "%s: invalid signature", path);
+	}
+}
+
+static void writeSignature(void) {
+	writeExpect(Signature, sizeof(Signature));
+}
+
+struct PACKED Chunk {
+	uint32_t size;
+	char type[4];
+};
+
+static const char *typeStr(struct Chunk chunk) {
+	static char buf[5];
+	memcpy(buf, chunk.type, 4);
+	return buf;
+}
+
+static struct Chunk readChunk(void) {
+	struct Chunk chunk;
+	readExpect(&chunk, sizeof(chunk), "chunk");
+	chunk.size = ntohl(chunk.size);
+	crc = crc32(CRC_INIT, (Byte *)chunk.type, sizeof(chunk.type));
+	return chunk;
+}
+
+static void writeChunk(struct Chunk chunk) {
+	chunk.size = htonl(chunk.size);
+	writeExpect(&chunk, sizeof(chunk));
+	crc = crc32(CRC_INIT, (Byte *)chunk.type, sizeof(chunk.type));
+}
+
+static void readCrc(void) {
+	uint32_t expected = crc;
+	uint32_t found;
+	readExpect(&found, sizeof(found), "CRC32");
+	found = ntohl(found);
+	if (found != expected) {
+		errx(
+			EX_DATAERR, "%s: expected CRC32 %08X, found %08X",
+			path, expected, found
+		);
+	}
+}
+
+static void writeCrc(void) {
+	uint32_t net = htonl(crc);
+	writeExpect(&net, sizeof(net));
+}
+
+static void skipChunk(struct Chunk chunk) {
+	uint8_t discard[chunk.size];
+	readExpect(discard, sizeof(discard), "chunk data");
+	readCrc();
+}
+
+static struct PACKED {
+	uint32_t width;
+	uint32_t height;
+	uint8_t depth;
+	enum PACKED {
+		Grayscale      = 0,
+		Truecolor      = 2,
+		Indexed        = 3,
+		GrayscaleAlpha = 4,
+		TruecolorAlpha = 6,
+	} color;
+	uint8_t compression;
+	uint8_t filter;
+	uint8_t interlace;
+} header;
+_Static_assert(13 == sizeof(header), "header size");
+
+static size_t pixelBits(void) {
+	switch (header.color) {
+		case Grayscale:      return 1 * header.depth;
+		case Truecolor:      return 3 * header.depth;
+		case Indexed:        return 1 * header.depth;
+		case GrayscaleAlpha: return 2 * header.depth;
+		case TruecolorAlpha: return 4 * header.depth;
+		default: abort();
+	}
+}
+
+static size_t pixelSize(void) {
+	return (pixelBits() + 7) / 8;
+}
+
+static size_t lineSize(void) {
+	return (header.width * pixelBits() + 7) / 8;
+}
+
+static size_t dataSize(void) {
+	return (1 + lineSize()) * header.height;
+}
+
+static void readHeader(void) {
+	struct Chunk ihdr = readChunk();
+	if (0 != memcmp(ihdr.type, "IHDR", 4)) {
+		errx(EX_DATAERR, "%s: expected IHDR, found %s", path, typeStr(ihdr));
+	}
+	if (ihdr.size != sizeof(header)) {
+		errx(
+			EX_DATAERR, "%s: expected IHDR size %zu, found %u",
+			path, sizeof(header), ihdr.size
+		);
+	}
+	readExpect(&header, sizeof(header), "header");
+	readCrc();
+	header.width = ntohl(header.width);
+	header.height = ntohl(header.height);
+	if (!header.width) errx(EX_DATAERR, "%s: invalid width 0", path);
+	if (!header.height) errx(EX_DATAERR, "%s: invalid height 0", path);
+}
+
+static void writeHeader(void) {
+	struct Chunk ihdr = { .size = sizeof(header), .type = "IHDR" };
+	writeChunk(ihdr);
+	header.width = htonl(header.width);
+	header.height = htonl(header.height);
+	writeExpect(&header, sizeof(header));
+	writeCrc();
+	header.width = ntohl(header.width);
+	header.height = ntohl(header.height);
+}
+
+static struct {
+	uint32_t len;
+	uint8_t entries[256][3];
+} palette;
+
+static void readPalette(void) {
+	struct Chunk chunk;
+	for (;;) {
+		chunk = readChunk();
+		if (0 == memcmp(chunk.type, "PLTE", 4)) break;
+		skipChunk(chunk);
+	}
+	palette.len = chunk.size / 3;
+	readExpect(palette.entries, chunk.size, "palette data");
+	readCrc();
+}
+
+static void writePalette(void) {
+	struct Chunk plte = { .size = 3 * palette.len, .type = "PLTE" };
+	writeChunk(plte);
+	writeExpect(palette.entries, plte.size);
+	writeCrc();
+}
+
+static uint8_t *data;
+
+static void readData(void) {
+	data = malloc(dataSize());
+	if (!data) err(EX_OSERR, "malloc(%zu)", dataSize());
+
+	struct z_stream_s stream = { .next_out = data, .avail_out = dataSize() };
+	int error = inflateInit(&stream);
+	if (error != Z_OK) errx(EX_SOFTWARE, "%s: inflateInit: %s", path, stream.msg);
+
+	for (;;) {
+		struct Chunk chunk = readChunk();
+		if (0 == memcmp(chunk.type, "IDAT", 4)) {
+			uint8_t *idat = malloc(chunk.size);
+			if (!idat) err(EX_OSERR, "malloc");
+
+			readExpect(idat, chunk.size, "image data");
+			readCrc();
+
+			stream.next_in = idat;
+			stream.avail_in = chunk.size;
+			int error = inflate(&stream, Z_SYNC_FLUSH);
+			free(idat);
+
+			if (error == Z_STREAM_END) break;
+			if (error != Z_OK) errx(EX_DATAERR, "%s: inflate: %s", path, stream.msg);
+
+		} else if (0 == memcmp(chunk.type, "IEND", 4)) {
+			errx(EX_DATAERR, "%s: missing IDAT chunk", path);
+		} else {
+			skipChunk(chunk);
+		}
+	}
+
+	inflateEnd(&stream);
+	if ((size_t)stream.total_out != dataSize()) {
+		errx(
+			EX_DATAERR, "%s: expected data size %zu, found %zu",
+			path, dataSize(), (size_t)stream.total_out
+		);
+	}
+}
+
+static void writeData(void) {
+	uLong size = compressBound(dataSize());
+	uint8_t *deflate = malloc(size);
+	if (!deflate) err(EX_OSERR, "malloc");
+
+	int error = compress2(deflate, &size, data, dataSize(), Z_BEST_SPEED);
+	if (error != Z_OK) errx(EX_SOFTWARE, "%s: compress2: %d", path, error);
+
+	struct Chunk idat = { .size = size, .type = "IDAT" };
+	writeChunk(idat);
+	writeExpect(deflate, size);
+	writeCrc();
+
+	free(deflate);
+}
+
+static void writeEnd(void) {
+	struct Chunk iend = { .size = 0, .type = "IEND" };
+	writeChunk(iend);
+	writeCrc();
+}
+
+enum PACKED Filter {
+	None,
+	Sub,
+	Up,
+	Average,
+	Paeth,
+	FilterCount,
+};
+
+static struct {
+	bool brokenPaeth;
+	bool filt;
+	bool recon;
+	uint8_t declareFilter;
+	uint8_t applyFilter;
+	enum Filter declareFilters[255];
+	enum Filter applyFilters[255];
+	bool invert;
+	bool mirror;
+	bool zeroX;
+	bool zeroY;
+} options;
+
+struct Bytes {
+	uint8_t x;
+	uint8_t a;
+	uint8_t b;
+	uint8_t c;
+};
+
+static uint8_t paethPredictor(struct Bytes f) {
+	int32_t p = (int32_t)f.a + (int32_t)f.b - (int32_t)f.c;
+	int32_t pa = abs(p - (int32_t)f.a);
+	int32_t pb = abs(p - (int32_t)f.b);
+	int32_t pc = abs(p - (int32_t)f.c);
+	if (pa <= pb && pa <= pc) return f.a;
+	if (options.brokenPaeth) {
+		if (pb < pc) return f.b;
+	} else {
+		if (pb <= pc) return f.b;
+	}
+	return f.c;
+}
+
+static uint8_t recon(enum Filter type, struct Bytes f) {
+	switch (type) {
+		case None:    return f.x;
+		case Sub:     return f.x + f.a;
+		case Up:      return f.x + f.b;
+		case Average: return f.x + ((uint32_t)f.a + (uint32_t)f.b) / 2;
+		case Paeth:   return f.x + paethPredictor(f);
+		default:      abort();
+	}
+}
+
+static uint8_t filt(enum Filter type, struct Bytes f) {
+	switch (type) {
+		case None:    return f.x;
+		case Sub:     return f.x - f.a;
+		case Up:      return f.x - f.b;
+		case Average: return f.x - ((uint32_t)f.a + (uint32_t)f.b) / 2;
+		case Paeth:   return f.x - paethPredictor(f);
+		default:      abort();
+	}
+}
+
+static struct Line {
+	enum Filter type;
+	uint8_t data[];
+} **lines;
+
+static void scanlines(void) {
+	lines = calloc(header.height, sizeof(*lines));
+	if (!lines) err(EX_OSERR, "calloc(%u, %zu)", header.height, sizeof(*lines));
+
+	size_t stride = 1 + lineSize();
+	for (uint32_t y = 0; y < header.height; ++y) {
+		lines[y] = (struct Line *)&data[y * stride];
+		if (lines[y]->type >= FilterCount) {
+			errx(EX_DATAERR, "%s: invalid filter type %hhu", path, lines[y]->type);
+		}
+	}
+}
+
+static struct Bytes origBytes(uint32_t y, size_t i) {
+	bool a = (i >= pixelSize()), b = (y > 0), c = (a && b);
+	return (struct Bytes) {
+		.x = lines[y]->data[i],
+		.a = a ? lines[y]->data[i - pixelSize()] : 0,
+		.b = b ? lines[y - 1]->data[i] : 0,
+		.c = c ? lines[y - 1]->data[i - pixelSize()] : 0,
+	};
+}
+
+static void reconData(void) {
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (size_t i = 0; i < lineSize(); ++i) {
+			if (options.filt) {
+				lines[y]->data[i] = filt(lines[y]->type, origBytes(y, i));
+			} else {
+				lines[y]->data[i] = recon(lines[y]->type, origBytes(y, i));
+			}
+		}
+		lines[y]->type = None;
+	}
+}
+
+static void filterData(void) {
+	for (uint32_t y = header.height - 1; y < header.height; --y) {
+		uint8_t filter[FilterCount][lineSize()];
+		uint32_t heuristic[FilterCount] = {0};
+		enum Filter minType = None;
+		for (enum Filter type = None; type < FilterCount; ++type) {
+			for (size_t i = 0; i < lineSize(); ++i) {
+				if (options.recon) {
+					filter[type][i] = recon(type, origBytes(y, i));
+				} else {
+					filter[type][i] = filt(type, origBytes(y, i));
+				}
+				heuristic[type] += abs((int8_t)filter[type][i]);
+			}
+			if (heuristic[type] < heuristic[minType]) minType = type;
+		}
+
+		if (options.declareFilter) {
+			lines[y]->type = options.declareFilters[y % options.declareFilter];
+		} else {
+			lines[y]->type = minType;
+		}
+
+		if (options.applyFilter) {
+			enum Filter type = options.applyFilters[y % options.applyFilter];
+			memcpy(lines[y]->data, filter[type], lineSize());
+		} else {
+			memcpy(lines[y]->data, filter[minType], lineSize());
+		}
+	}
+}
+
+static void invert(void) {
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (size_t i = 0; i < lineSize(); ++i) {
+			lines[y]->data[i] ^= 0xFF;
+		}
+	}
+}
+
+static void mirror(void) {
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (size_t i = 0, j = lineSize() - 1; i < j; ++i, --j) {
+			uint8_t t = lines[y]->data[i];
+			lines[y]->data[i] = lines[y]->data[j];
+			lines[y]->data[j] = t;
+		}
+	}
+}
+
+static void zeroX(void) {
+	for (uint32_t y = 0; y < header.height; ++y) {
+		memset(lines[y]->data, 0, pixelSize());
+	}
+}
+
+static void zeroY(void) {
+	memset(lines[0]->data, 0, lineSize());
+}
+
+static void glitch(const char *inPath, const char *outPath) {
+	if (inPath) {
+		path = inPath;
+		file = fopen(path, "r");
+		if (!file) err(EX_NOINPUT, "%s", path);
+	} else {
+		path = "(stdin)";
+		file = stdin;
+	}
+
+	readSignature();
+	readHeader();
+	if (header.color == Indexed) readPalette();
+	readData();
+	fclose(file);
+
+	scanlines();
+	reconData();
+	filterData();
+	if (options.invert) invert();
+	if (options.mirror) mirror();
+	if (options.zeroX) zeroX();
+	if (options.zeroY) zeroY();
+	free(lines);
+
+	if (outPath) {
+		path = outPath;
+		file = fopen(path, "w");
+		if (!file) err(EX_CANTCREAT, "%s", path);
+	} else {
+		path = "(stdout)";
+		file = stdout;
+	}
+
+	writeSignature();
+	writeHeader();
+	if (header.color == Indexed) writePalette();
+	writeData();
+	writeEnd();
+	free(data);
+
+	int error = fclose(file);
+	if (error) err(EX_IOERR, "%s", path);
+}
+
+static enum Filter parseFilter(const char *s) {
+	switch (s[0]) {
+		case 'N': case 'n': return None;
+		case 'S': case 's': return Sub;
+		case 'U': case 'u': return Up;
+		case 'A': case 'a': return Average;
+		case 'P': case 'p': return Paeth;
+		default: errx(EX_USAGE, "invalid filter type %s", s);
+	}
+}
+
+static uint8_t parseFilters(enum Filter *filters, const char *s) {
+	uint8_t len = 0;
+	do {
+		filters[len++] = parseFilter(s);
+		s = strchr(s, ',');
+	} while (s++);
+	return len;
+}
+
+int main(int argc, char *argv[]) {
+	bool stdio = false;
+	char *output = NULL;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "a:cd:fimo:prxy"))) {
+		switch (opt) {
+			break; case 'a':
+				options.applyFilter = parseFilters(options.applyFilters, optarg);
+			break; case 'c': stdio = true;
+			break; case 'd':
+				options.declareFilter = parseFilters(options.declareFilters, optarg);
+			break; case 'f': options.filt = true;
+			break; case 'i': options.invert = true;
+			break; case 'm': options.mirror = true;
+			break; case 'o': output = optarg;
+			break; case 'p': options.brokenPaeth = true;
+			break; case 'r': options.recon = true;
+			break; case 'x': options.zeroX = true;
+			break; case 'y': options.zeroY = true;
+			break; default: return EX_USAGE;
+		}
+	}
+
+	if (argc - optind == 1 && (output || stdio)) {
+		glitch(argv[optind], output);
+	} else if (optind < argc) {
+		for (int i = optind; i < argc; ++i) {
+			glitch(argv[i], argv[i]);
+		}
+	} else {
+		glitch(NULL, output);
+	}
+
+	return EX_OK;
+}
diff --git a/bin/hi.c b/bin/hi.c
new file mode 100644
index 00000000..b39c0af4
--- /dev/null
+++ b/bin/hi.c
@@ -0,0 +1,766 @@
+/* vim: set foldmethod=marker foldlevel=0: */
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <err.h>
+#include <locale.h>
+#include <regex.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+#define ARRAY_LEN(a) (sizeof(a) / sizeof(a[0]))
+
+typedef unsigned Set;
+#define SET(x) ((Set)1 << (x))
+
+#define ENUM_CLASS \
+	X(Normal)  \
+	X(Keyword) \
+	X(Macro)   \
+	X(Tag)     \
+	X(String)  \
+	X(Escape)  \
+	X(Format)  \
+	X(Interp)  \
+	X(Comment) \
+	X(Todo)    \
+	X(DiffOld) \
+	X(DiffNew)
+
+enum Class {
+#define X(class) class,
+	ENUM_CLASS
+#undef X
+	ClassLen,
+};
+
+static const char *ClassName[ClassLen] = {
+#define X(class) [class] = #class,
+	ENUM_CLASS
+#undef X
+};
+
+struct Syntax {
+	enum Class class;
+	Set parent;
+	bool newline;
+	size_t subexp;
+	const char *pattern;
+};
+
+#define WB "(^|[^_[:alnum:]]|\n)"
+#define BL0 "[[:blank:]]*"
+#define BL1 "[[:blank:]]+"
+#define SP0 "[[:space:]]*"
+#define SP1 "[[:space:]]+"
+#define PATTERN_ID "[_[:alpha:]][_[:alnum:]]*"
+#define PATTERN_SQ "'([^']|[\\]')*'"
+#define PATTERN_DQ "\"([^\"]|[\\]\")*\""
+#define PATTERN_BC "/[*]" "([^*]|[*][^/])*" "[*]+/"
+#define PATTERN_TODO "FIXME|TODO|XXX"
+
+// C syntax {{{
+static const struct Syntax CSyntax[] = {
+	{ Keyword, .subexp = 2, .pattern = WB
+		"(" "auto|extern|register|static|(_T|t)hread_local|typedef"
+		"|" "_Atomic|const|restrict|volatile"
+		"|" "inline|(_N|n)oreturn"
+		"|" "(_A|a)lignas"
+		"|" "enum|struct|union"
+		"|" "do|else|for|if|switch|while"
+		"|" "break|case|continue|default|goto|return"
+		")" WB },
+	{ Macro,
+		.pattern = "^" BL0 "#(.|[\\]\n)*" },
+	{ Tag, .parent = SET(Macro), .subexp = 1,
+		.pattern = "define" BL1 "(" PATTERN_ID ")" "[(]" },
+	{ Tag, .subexp = 2,
+		.pattern = "(enum|struct|union)" SP1 "(" PATTERN_ID ")" SP0 "[{]" },
+	{ Tag, .parent = ~SET(Keyword), .newline = true, .subexp = 1,
+		.pattern = "(" PATTERN_ID ")" SP0 "[(][^()]*[)]" SP0 "[{]" },
+	{ Tag, .newline = true, .subexp = 3, .pattern =
+		"(static|typedef)" SP1
+		"(" "(" PATTERN_ID ")" SP0
+		"(" "[*]" "|" "[[][^]]*[]]" "|" "[{][^}]*[}]" "|" SP0 ")*" ")+" },
+	{ String, .parent = SET(Macro), .subexp = 2,
+		.pattern = "(include|import)" BL0 "(<[^>]*>)" },
+	{ String,
+		.pattern = "[LUu]?" PATTERN_SQ },
+	{ String, .parent = ~SET(String),
+		.pattern = "([LU]|u8?)?" PATTERN_DQ },
+	{ Escape, .parent = SET(String),
+		.pattern = "[\\]([\"'?\\abfnrtv]|[0-7]{1,3}|x[0-9A-Fa-f]+)" },
+	{ Escape, .parent = SET(String),
+		.pattern = "[\\](U[0-9A-Fa-f]{8}|u[0-9A-Fa-f]{4})" },
+	{ Format, .parent = SET(String), .pattern =
+		"%%|%[ #+-0]*"         // flags
+		"([*]|[0-9]+)?"        // field width
+		"([.]([*]|[0-9]+))?"   // precision
+		"([Lhjltz]|hh|ll)?"    // length modifier
+		"[AEFGXacdefginopsux]" // format specifier
+	},
+	{ Comment, .parent = ~SET(String),
+		.pattern = "//(.|[\\]\n)*" },
+	{ Comment, .parent = ~SET(String), .newline = true,
+		.pattern = PATTERN_BC },
+	{ Todo, .parent = SET(Comment),
+		.pattern = PATTERN_TODO },
+};
+// }}}
+
+// diff syntax {{{
+static const struct Syntax DiffSyntax[] = {
+	{ Keyword, .pattern = "^[^ ].*" },
+	{ Comment, .pattern = "^@@.*" },
+	{ DiffOld, .pattern = "^[-].*" },
+	{ DiffNew, .pattern = "^[+].*" },
+};
+// }}}
+
+// make syntax {{{
+#define MAKE_TARGET "[-./_[:alnum:]]+"
+static const struct Syntax MakeSyntax[] = {
+	{ Keyword, .subexp = 2,
+		.pattern = WB "([.](PHONY|PRECIOUS|SUFFIXES))" WB },
+	{ Macro,
+		.pattern = "^ *-?include" },
+	{ Tag, .parent = ~SET(Keyword), .subexp = 1, .pattern =
+		"(" MAKE_TARGET ")" "(" BL1 MAKE_TARGET ")*" BL0 ":([^=]|$)" },
+	{ String, .subexp = 1,
+		.pattern = "[._[:alnum:]]+" BL0 "[!+:?]?=" BL0 "(.*)" },
+	{ Normal,
+		.pattern = "^\t.*" },
+	{ String,
+		.pattern = PATTERN_SQ },
+	{ String,
+		.pattern = PATTERN_DQ },
+	{ Interp,
+		.pattern = "[$]." },
+	// Support one level of nesting with the same delimiter.
+	{ Interp,
+		.pattern = "[$][(](" "[^$)]" "|" "[$]." "|" "[$][(][^)]*[)]" ")*[)]" },
+	{ Interp,
+		.pattern = "[$][{](" "[^$}]" "|" "[$]." "|" "[$][{][^}]*[}]" ")*[}]" },
+	{ Escape,
+		.pattern = "[$][$]" },
+	{ Comment, .parent = ~SET(String),
+		.pattern = "#.*" },
+	{ Todo, .parent = SET(Comment),
+		.pattern = PATTERN_TODO },
+};
+// }}}
+
+// mdoc syntax {{{
+static const struct Syntax MdocSyntax[] = {
+	{ Keyword, .subexp = 2, .pattern = WB
+		"(" "D[dt]|N[dm]|Os"
+		"|" "S[hsx]|[LP]p|Xr"
+		"|" "%[ABCDIJNOPQRTUV]|[BE][dl]|D[1l]|It|Ql|R[es]|Ta"
+		"|" "Ap|[BE]k|Ns|Pf|Sm"
+		"|" "Ar|Cm|Ev|Fl|O[cop]|Pa"
+		"|" "Dv|Er|F[acdnot]|In|Lb|V[at]"
+		"|" "A[dn]|Cd|Lk|M[st]"
+		"|" "[BE]f|Em|Li|No|Sy"
+		"|" "(Br|[ABDPQS])[coq]|E[co]"
+		"|" "At|(Bs|[BDEFNO])x|Rv|St"
+		")" WB },
+	{ Tag, .subexp = 1,
+		.pattern = "^[.]S[hs]" BL1 "(.+)" },
+	{ String,
+		.pattern = PATTERN_DQ },
+	{ Normal,
+		.pattern = "^[^.].*" },
+	{ String,
+		.pattern = "[\\](" "." "|" "[(].{2}" "|" "[[][^]]*[]]" ")" },
+	{ Comment,
+		.pattern = "^[.][\\]\".*" },
+	{ Todo, .parent = SET(Comment),
+		.pattern = PATTERN_TODO },
+};
+// }}}
+
+// Rust syntax {{{
+static const struct Syntax RustSyntax[] = {
+	{ Keyword, .subexp = 2, .pattern = WB
+		"(" "'?static|[Ss]elf|abstract|as|async|await|become|box|break|const"
+		"|" "continue|crate|do|dyn|else|enum|extern|false|final|fn|for|if"
+		"|" "impl|in|let|loop|macro|match|mod|move|mut|override|priv|pub|ref"
+		"|" "return|struct|super|trait|true|try|type(of)?|union|uns(afe|ized)"
+		"|" "use|virtual|where|while|yield"
+		")" WB },
+	{ Tag, .subexp = 2, .pattern =
+		"(enum|fn|macro_rules!|mod|struct|type|union)" SP1 "(" PATTERN_ID ")" },
+	{ Macro, .newline = true,
+		.pattern = "#!?[[][^]]*[]]" },
+	{ Macro,
+		.pattern = PATTERN_ID "!" },
+	{ Interp,
+		.pattern = "[$]" PATTERN_ID },
+	{ String,
+		.pattern = "b?'([^']|[\\]')'" },
+	{ String,
+		.pattern = "b?" "\"([^\"]|[\\][\n\"])*\"" },
+	{ Escape, .parent = SET(String),
+		.pattern = "[\\]([\"'0\\nrt]|u[{][0-9A-Fa-f]{1,6}[}]|x[0-9A-Fa-f]{2})" },
+	{ Format, .parent = SET(String),
+		.pattern = "[{][{]|[{][^{}]*[}]|[}][}]" },
+	{ String, .parent = ~SET(String), .newline = true,
+		.pattern = "b?r\"[^\"]*\"" },
+	{ String, .parent = ~SET(String), .newline = true,
+		.pattern = "b?r#+\"" "([^\"]|\"[^#])*" "\"+#+" },
+	{ Comment, .parent = ~SET(String),
+		.pattern = "//.*" },
+	{ Comment, .parent = ~SET(String), .newline = true,
+		.pattern = PATTERN_BC },
+	{ Todo, .parent = SET(Comment),
+		.pattern = PATTERN_TODO },
+};
+// }}}
+
+// sh syntax {{{
+static const struct Syntax ShSyntax[] = {
+	{ Keyword, .subexp = 2, .pattern = WB
+		"(" "!|case|do|done|elif|else|esac|fi|for|if|in|then|until|while"
+		"|" "alias|bg|cd|command|false|fc|fg|getopts|jobs|kill|newgrp|pwd|read"
+		"|" "true|type|ulimit|umask|unalias|wait"
+		"|" "[.:]|break|continue|eval|exec|exit|export|local|readonly|return"
+		"|" "set|shift|times|trap|unset"
+		")" WB },
+	{ Tag, .subexp = 2,
+		.pattern = WB "(" PATTERN_ID ")" BL0 "[(]" BL0 "[)]" },
+	{ String, .newline = true, .subexp = 1, .pattern =
+		"<<-?" BL0 "EOF[^\n]*\n"
+		"(([^\n]|\n\t*[^E]|\n\t*E[^O]|\n\t*EO[^F]|\n\t*EOF[^\n])*)"
+		"\n\t*EOF\n" },
+	{ String, .parent = ~SET(String), .newline = true,
+		.pattern = PATTERN_DQ },
+	{ Escape, .parent = SET(String),
+		.pattern = "[\\][\"$\\`]" },
+	{ Interp, .parent = ~SET(Escape),
+		.pattern = "[$][(][^)]*[)]" "|" "`[^`]*`" },
+	{ Interp, .parent = ~SET(Escape),
+		.pattern = "[$][(][(]([^)]|[)][^)])*[)][)]" },
+	{ String, .parent = SET(Interp),
+		.pattern = PATTERN_DQ },
+	{ Interp, .parent = ~SET(Escape),
+		.pattern = "[$]([!#$*?@-]|[_[:alnum:]]+|[{][^}]*[}])" },
+	{ String, .parent = ~SET(Escape),
+		.pattern = "[\\]." },
+	{ String, .subexp = 1, .newline = true, .pattern =
+		"<<-?" BL0 "'EOF'[^\n]*\n"
+		"(([^\n]|\n\t*[^E]|\n\t*E[^O]|\n\t*EO[^F]|\n\t*EOF[^\n])*)"
+		"\n\t*EOF\n" },
+	{ String, .parent = ~SET(String), .newline = true,
+		.pattern = "'[^']*'" },
+	{ Comment, .parent = ~SET(String), .subexp = 2,
+		.pattern = "(^|[[:blank:]]+)(#.*)" },
+	{ Todo, .parent = SET(Comment),
+		.pattern = PATTERN_TODO },
+};
+// }}}
+
+static const struct Language {
+	const char *name;
+	const char *pattern;
+	const struct Syntax *syntax;
+	size_t len;
+} Languages[] = {
+	{ "c",    "[.][chlmy]$", CSyntax, ARRAY_LEN(CSyntax) },
+	{ "diff", "[.](diff|patch)$", DiffSyntax, ARRAY_LEN(DiffSyntax) },
+	{ "make", "[.]mk$|^Makefile$", MakeSyntax, ARRAY_LEN(MakeSyntax) },
+	{ "mdoc", "[.][1-9]$", MdocSyntax, ARRAY_LEN(MdocSyntax) },
+	{ "rust", "[.]rs$", RustSyntax, ARRAY_LEN(RustSyntax) },
+	{ "sh",   "[.](sh|in)$|^[.](profile|shrc)$", ShSyntax, ARRAY_LEN(ShSyntax) },
+	{ "text", "[.]txt$", NULL, 0 },
+};
+
+static regex_t compile(const char *pattern, int flags) {
+	regex_t regex;
+	int error = regcomp(&regex, pattern, REG_EXTENDED | flags);
+	if (!error) return regex;
+	char buf[256];
+	regerror(error, &regex, buf, sizeof(buf));
+	errx(EX_SOFTWARE, "regcomp: %s: %s", buf, pattern);
+}
+
+enum { SubsLen = 8 };
+static void highlight(struct Language lang, enum Class *hi, const char *str) {
+	for (size_t i = 0; i < lang.len; ++i) {
+		struct Syntax syn = lang.syntax[i];
+		regex_t regex = compile(syn.pattern, syn.newline ? 0 : REG_NEWLINE);
+		assert(syn.subexp < SubsLen);
+		assert(syn.subexp <= regex.re_nsub);
+		regmatch_t subs[SubsLen] = {{0}};
+		for (size_t offset = 0; str[offset]; offset += subs[syn.subexp].rm_eo) {
+			int error = regexec(
+				&regex, &str[offset], SubsLen, subs, offset ? REG_NOTBOL : 0
+			);
+			if (error == REG_NOMATCH) break;
+			if (error) errx(EX_SOFTWARE, "regexec: %d", error);
+			regmatch_t *sub = &subs[syn.subexp];
+			if (syn.parent && !(syn.parent & SET(hi[offset + sub->rm_so]))) {
+				sub->rm_eo = sub->rm_so + 1;
+				continue;
+			}
+			for (regoff_t j = sub->rm_so; j < sub->rm_eo; ++j) {
+				hi[offset + j] = lang.syntax[i].class;
+			}
+		}
+		regfree(&regex);
+	}
+}
+
+static void check(void) {
+	for (size_t i = 0; i < ARRAY_LEN(Languages); ++i) {
+		regex_t regex = compile(Languages[i].pattern, REG_NOSUB);
+		regfree(&regex);
+		for (size_t j = 0; j < Languages[i].len; ++j) {
+			struct Syntax syn = Languages[i].syntax[j];
+			regex = compile(syn.pattern, 0);
+			if (syn.subexp >= SubsLen || syn.subexp > regex.re_nsub) {
+				errx(
+					EX_SOFTWARE, "subexpression %zu out of bounds: %s",
+					syn.subexp, syn.pattern
+				);
+			}
+			regfree(&regex);
+		}
+	}
+}
+
+#define ENUM_OPTION \
+	X(Anchor, "anchor") \
+	X(CSS, "css") \
+	X(Document, "document") \
+	X(Inline, "inline") \
+	X(Monospace, "monospace") \
+	X(Tab, "tab") \
+	X(Title, "title")
+
+enum Option {
+#define X(option, _) option,
+	ENUM_OPTION
+#undef X
+	OptionLen,
+};
+
+static const char *OptionKey[OptionLen + 1] = {
+#define X(option, key) [option] = key,
+	ENUM_OPTION
+#undef X
+	NULL,
+};
+
+typedef void HeaderFn(const char *opts[]);
+typedef void
+OutputFn(const char *opts[], enum Class class, const char *str, size_t len);
+
+// ANSI format {{{
+
+enum SGR {
+	SGRBoldOn = 1,
+	SGRUnderlineOn = 4,
+	SGRBoldOff = 22,
+	SGRUnderlineOff = 24,
+	SGRBlack = 30,
+	SGRRed,
+	SGRGreen,
+	SGRYellow,
+	SGRBlue,
+	SGRMagenta,
+	SGRCyan,
+	SGRWhite,
+	SGRDefault = 39,
+};
+
+static const enum SGR ANSIStyle[ClassLen][3] = {
+	[Normal]  = { SGRDefault },
+	[Keyword] = { SGRWhite },
+	[Macro]   = { SGRGreen },
+	[Tag]     = { SGRDefault, SGRUnderlineOn, SGRUnderlineOff },
+	[String]  = { SGRCyan },
+	[Escape]  = { SGRDefault },
+	[Format]  = { SGRCyan, SGRBoldOn, SGRBoldOff },
+	[Interp]  = { SGRYellow },
+	[Comment] = { SGRBlue },
+	[Todo]    = { SGRBlue, SGRBoldOn, SGRBoldOff },
+	[DiffOld] = { SGRRed },
+	[DiffNew] = { SGRGreen },
+};
+
+static void
+ansiOutput(const char *opts[], enum Class class, const char *str, size_t len) {
+	(void)opts;
+	if (ANSIStyle[class][1]) {
+		printf(
+			"\x1B[%d;%dm%.*s\x1B[%dm",
+			ANSIStyle[class][0], ANSIStyle[class][1],
+			(int)len, str,
+			ANSIStyle[class][2]
+		);
+	} else {
+		printf("\x1B[%dm%.*s", ANSIStyle[class][0], (int)len, str);
+	}
+}
+
+// }}}
+
+// IRC format {{{
+
+enum IRC {
+	IRCWhite,
+	IRCBlack,
+	IRCBlue,
+	IRCGreen,
+	IRCRed,
+	IRCBrown,
+	IRCMagenta,
+	IRCOrange,
+	IRCYellow,
+	IRCLightGreen,
+	IRCCyan,
+	IRCLightCyan,
+	IRCLightBlue,
+	IRCPink,
+	IRCGray,
+	IRCLightGray,
+	IRCBold = 0x02,
+	IRCColor = 0x03,
+	IRCMonospace = 0x11,
+	IRCUnderline = 0x1F,
+};
+
+static const enum IRC SGRIRC[] = {
+	[SGRBoldOn]  = IRCBold,
+	[SGRBoldOff] = IRCBold,
+	[SGRUnderlineOn]  = IRCUnderline,
+	[SGRUnderlineOff] = IRCUnderline,
+	[SGRBlack]   = IRCBlack,
+	[SGRRed]     = IRCRed,
+	[SGRGreen]   = IRCGreen,
+	[SGRYellow]  = IRCYellow,
+	[SGRBlue]    = IRCBlue,
+	[SGRMagenta] = IRCMagenta,
+	[SGRCyan]    = IRCCyan,
+	[SGRWhite]   = IRCGray,
+	[SGRDefault] = 0,
+};
+
+static void ircHeader(const char *opts[]) {
+	if (opts[Monospace]) printf("%c", IRCMonospace);
+}
+
+static void
+ircOutput(const char *opts[], enum Class class, const char *str, size_t len) {
+	char cc[3] = "";
+	if (ANSIStyle[class][0] != SGRDefault) {
+		snprintf(cc, sizeof(cc), "%d", SGRIRC[ANSIStyle[class][0]]);
+	}
+	// Prevent trailing formatting after newline ...
+	bool newline = (str[len - 1] == '\n');
+	if (ANSIStyle[class][1]) {
+		printf(
+			"%c%s%c%.*s%c%s",
+			IRCColor, cc, SGRIRC[ANSIStyle[class][1]],
+			(int)(newline ? len - 1 : len), str,
+			SGRIRC[ANSIStyle[class][2]],
+			(newline ? "\n" : "")
+		);
+	} else {
+		// Double-toggle bold to prevent str being interpreted as color.
+		printf("%c%s%c%c%.*s", IRCColor, cc, IRCBold, IRCBold, (int)len, str);
+	}
+	// ... except for monospace, at the beginning of each line.
+	if (newline && opts[Monospace]) printf("%c", IRCMonospace);
+}
+
+// }}}
+
+// HTML format {{{
+
+static void htmlEscape(const char *str, size_t len) {
+	while (len) {
+		size_t run = strcspn(str, "\"&<>");
+		if (run > len) run = len;
+		switch (str[0]) {
+			break; case '"': run = 1; printf("&quot;");
+			break; case '&': run = 1; printf("&amp;");
+			break; case '<': run = 1; printf("&lt;");
+			break; case '>': run = 1; printf("&gt;");
+			break; default:  printf("%.*s", (int)run, str);
+		}
+		str += run;
+		len -= run;
+	}
+}
+
+static const char *HTMLStyle[ClassLen] = {
+	[Keyword] = "color: dimgray;",
+	[Macro]   = "color: green;",
+	[Tag]     = "color: inherit; text-decoration: underline;",
+	[String]  = "color: teal;",
+	[Format]  = "color: teal; font-weight: bold;",
+	[Interp]  = "color: olive;",
+	[Comment] = "color: navy;",
+	[Todo]    = "color: navy; font-weight: bold;",
+	[DiffOld] = "color: red;",
+	[DiffNew] = "color: green;",
+};
+
+static void htmlTabSize(const char *tab) {
+	printf("-moz-tab-size: ");
+	htmlEscape(tab, strlen(tab));
+	printf("; tab-size: ");
+	htmlEscape(tab, strlen(tab));
+	printf(";");
+}
+
+static void htmlHeader(const char *opts[]) {
+	if (!opts[Document]) goto body;
+	printf("<!DOCTYPE html>\n<title>");
+	if (opts[Title]) htmlEscape(opts[Title], strlen(opts[Title]));
+	printf("</title>\n");
+	if (opts[CSS]) {
+		printf("<link rel=\"stylesheet\" href=\"");
+		htmlEscape(opts[CSS], strlen(opts[CSS]));
+		printf("\">\n");
+	} else if (!opts[Inline]) {
+		printf("<style>\n");
+		if (opts[Tab]) {
+			printf("pre.hi { ");
+			htmlTabSize(opts[Tab]);
+			printf(" }\n");
+		}
+		for (enum Class class = 0; class < ClassLen; ++class) {
+			if (!HTMLStyle[class]) continue;
+			printf(".hi.%s { %s }\n", ClassName[class], HTMLStyle[class]);
+		}
+		printf(
+			".hi.%s:target { color: goldenrod; outline: none; }\n",
+			ClassName[Tag]
+		);
+		printf("</style>\n");
+	}
+body:
+	if (opts[Inline] && opts[Tab]) {
+		printf("<pre class=\"hi\" style=\"");
+		htmlTabSize(opts[Tab]);
+		printf("\">");
+	} else {
+		printf("<pre class=\"hi\">");
+	}
+}
+
+static void htmlFooter(const char *opts[]) {
+	(void)opts;
+	printf("</pre>\n");
+}
+
+static void htmlAnchor(const char *opts[], const char *str, size_t len) {
+	if (opts[Inline]) {
+		printf("<a style=\"%s\" id=\"", HTMLStyle[Tag] ? HTMLStyle[Tag] : "");
+	} else {
+		printf("<a class=\"hi %s\" id=\"", ClassName[Tag]);
+	}
+	htmlEscape(str, len);
+	printf("\" href=\"#");
+	htmlEscape(str, len);
+	printf("\">");
+	htmlEscape(str, len);
+	printf("</a>");
+}
+
+static void
+htmlOutput(const char *opts[], enum Class class, const char *str, size_t len) {
+	if (opts[Anchor] && class == Tag) {
+		htmlAnchor(opts, str, len);
+		return;
+	}
+	if (opts[Inline]) {
+		printf("<span style=\"%s\">", HTMLStyle[class] ? HTMLStyle[class] : "");
+	} else {
+		printf("<span class=\"hi %s\">", ClassName[class]);
+	}
+	htmlEscape(str, len);
+	printf("</span>");
+}
+
+// }}}
+
+// Debug format {{{
+static void
+debugOutput(const char *opts[], enum Class class, const char *str, size_t len) {
+	(void)opts;
+	printf("%s\t\"", ClassName[class]);
+	while (len) {
+		size_t run = strcspn(str, "\t\n\"\\");
+		if (run > len) run = len;
+		switch (str[0]) {
+			break; case '\t': run = 1; printf("\\t");
+			break; case '\n': run = 1; printf("\\n");
+			break; case '"':  run = 1; printf("\\\"");
+			break; case '\\': run = 1; printf("\\\\");
+			break; default:   printf("%.*s", (int)run, str);
+		}
+		str += run;
+		len -= run;
+	}
+	printf("\"\n");
+}
+// }}}
+
+static const struct Format {
+	const char *name;
+	OutputFn *output;
+	HeaderFn *header;
+	HeaderFn *footer;
+} Formats[] = {
+	{ "ansi",  ansiOutput, NULL, NULL },
+	{ "irc",   ircOutput, ircHeader, NULL },
+	{ "html",  htmlOutput, htmlHeader, htmlFooter },
+	{ "debug", debugOutput, NULL, NULL },
+};
+
+static bool findLanguage(struct Language *lang, const char *name) {
+	for (size_t i = 0; i < ARRAY_LEN(Languages); ++i) {
+		if (strcmp(name, Languages[i].name)) continue;
+		*lang = Languages[i];
+		return true;
+	}
+	return false;
+}
+
+static bool matchLanguage(struct Language *lang, const char *name) {
+	for (size_t i = 0; i < ARRAY_LEN(Languages); ++i) {
+		regex_t regex = compile(Languages[i].pattern, REG_NOSUB);
+		int error = regexec(&regex, name, 0, NULL, 0);
+		regfree(&regex);
+		if (error == REG_NOMATCH) continue;
+		if (error) errx(EX_SOFTWARE, "regexec: %d", error);
+		*lang = Languages[i];
+		return true;
+	}
+	return false;
+}
+
+static bool findFormat(struct Format *format, const char *name) {
+	for (size_t i = 0; i < ARRAY_LEN(Formats); ++i) {
+		if (strcmp(name, Formats[i].name)) continue;
+		*format = Formats[i];
+		return true;
+	}
+	return false;
+}
+
+int main(int argc, char *argv[]) {
+	setlocale(LC_CTYPE, "");
+
+	bool text = false;
+	const char *name = NULL;
+	struct Language lang = {0};
+	struct Format format = Formats[0];
+	const char *opts[OptionLen] = {0};
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "cf:l:n:o:t"))) {
+		switch (opt) {
+			break; case 'c': check(); return EX_OK;
+			break; case 'f': {
+				if (!findFormat(&format, optarg)) {
+					errx(EX_USAGE, "no such format %s", optarg);
+				}
+			}
+			break; case 'l': {
+				if (!findLanguage(&lang, optarg)) {
+					errx(EX_USAGE, "no such language %s", optarg);
+				}
+			}
+			break; case 'n': name = optarg;
+			break; case 'o': {
+				char *val;
+				enum Option key;
+				while (optarg[0]) {
+					key = getsubopt(&optarg, (char *const *)OptionKey, &val);
+					if (key >= OptionLen) {
+						errx(EX_USAGE, "no such option %s", val);
+					}
+					opts[key] = (val ? val : "");
+				}
+			}
+			break; case 't': text = true;
+			break; default: return EX_USAGE;
+		}
+	}
+
+	const char *path = "(stdin)";
+	FILE *file = stdin;
+	if (optind < argc) {
+		path = argv[optind];
+		file = fopen(path, "r");
+		if (!file) err(EX_NOINPUT, "%s", path);
+	}
+
+	if (!name) {
+		name = strrchr(path, '/');
+		name = (name ? &name[1] : path);
+	}
+	if (!lang.name && !matchLanguage(&lang, name) && !text) {
+		errx(EX_USAGE, "cannot infer language for %s", name);
+	}
+	if (!opts[Title]) opts[Title] = name;
+
+	struct stat stat;
+	int error = fstat(fileno(file), &stat);
+	if (error) err(EX_IOERR, "fstat");
+
+	size_t cap = (stat.st_mode & S_IFREG ? stat.st_size + 1 : 4096);
+	char *str = malloc(cap);
+	if (!str) err(EX_OSERR, "malloc");
+
+	size_t len = 0, read;
+	while (0 < (read = fread(&str[len], 1, cap - len - 1, file))) {
+		len += read;
+		if (len + 1 < cap) continue;
+		cap *= 2;
+		str = realloc(str, cap);
+		if (!str) err(EX_OSERR, "realloc");
+	}
+	if (ferror(file)) err(EX_IOERR, "fread");
+	if (memchr(str, 0, len)) errx(EX_DATAERR, "input is binary");
+	str[len] = '\0';
+
+	enum Class *hi = calloc(len, sizeof(*hi));
+	if (!hi) err(EX_OSERR, "calloc");
+
+	highlight(lang, hi, str);
+
+	size_t run = 0;
+	if (format.header) format.header(opts);
+	for (size_t i = 0; i < len; i += run) {
+		for (run = 1; i + run < len; ++run) {
+			if (hi[i + run] != hi[i]) break;
+			if (str[i + run - 1] == '\n') break;
+		}
+		format.output(opts, hi[i], &str[i], run);
+	}
+	if (format.footer) format.footer(opts);
+}
diff --git a/bin/hnel.c b/bin/hnel.c
new file mode 100644
index 00000000..4a869c2d
--- /dev/null
+++ b/bin/hnel.c
@@ -0,0 +1,120 @@
+/* Copyright (C) 2017  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+
+#if defined __FreeBSD__
+#include <libutil.h>
+#elif defined __linux__
+#include <pty.h>
+#else
+#include <util.h>
+#endif
+
+typedef unsigned char byte;
+
+static struct termios saveTerm;
+static void restoreTerm(void) {
+	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+
+	if (argc < 4) return EX_USAGE;
+
+	byte table[256] = {0};
+	if (strlen(argv[1]) != strlen(argv[2])) return EX_USAGE;
+	for (const char *from = argv[1], *to = argv[2]; *from; ++from, ++to) {
+		table[(byte)*from] = *to;
+	}
+
+	error = tcgetattr(STDERR_FILENO, &saveTerm);
+	if (error) err(EX_IOERR, "tcgetattr");
+	atexit(restoreTerm);
+
+	struct termios raw = saveTerm;
+	cfmakeraw(&raw);
+	error = tcsetattr(STDERR_FILENO, TCSADRAIN, &raw);
+	if (error) err(EX_IOERR, "tcsetattr");
+
+	struct winsize window;
+	error = ioctl(STDERR_FILENO, TIOCGWINSZ, &window);
+	if (error) err(EX_IOERR, "TIOCGWINSZ");
+
+	int pty;
+	pid_t pid = forkpty(&pty, NULL, NULL, &window);
+	if (pid < 0) err(EX_OSERR, "forkpty");
+
+	if (!pid) {
+		execvp(argv[3], &argv[3]);
+		err(EX_NOINPUT, "%s", argv[3]);
+	}
+
+	bool enable = true;
+
+	byte buf[4096];
+	struct pollfd fds[2] = {
+		{ .fd = STDIN_FILENO, .events = POLLIN },
+		{ .fd = pty, .events = POLLIN },
+	};
+	while (0 < poll(fds, 2, -1)) {
+		if (fds[0].revents & POLLIN) {
+			ssize_t readSize = read(STDIN_FILENO, buf, sizeof(buf));
+			if (readSize < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
+
+			if (readSize == 1) {
+				if (buf[0] == CTRL('S')) {
+					enable ^= true;
+					continue;
+				}
+
+				byte c = buf[0];
+				if (enable && table[c]) buf[0] = table[c];
+			}
+
+			ssize_t writeSize = write(pty, buf, readSize);
+			if (writeSize < 0) err(EX_IOERR, "write(%d)", pty);
+			if (writeSize < readSize) errx(EX_IOERR, "short write(%d)", pty);
+		}
+
+		if (fds[1].revents & POLLIN) {
+			ssize_t readSize = read(pty, buf, sizeof(buf));
+			if (readSize < 0) err(EX_IOERR, "read(%d)", pty);
+
+			ssize_t writeSize = write(STDOUT_FILENO, buf, readSize);
+			if (writeSize < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
+			if (writeSize < readSize) {
+				errx(EX_IOERR, "short write(%d)", STDOUT_FILENO);
+			}
+		}
+
+		int status;
+		pid_t dead = waitpid(pid, &status, WNOHANG);
+		if (dead < 0) err(EX_OSERR, "waitpid(%d)", pid);
+		if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
+	}
+	err(EX_IOERR, "poll");
+}
diff --git a/bin/html.sh b/bin/html.sh
new file mode 100644
index 00000000..e96a7210
--- /dev/null
+++ b/bin/html.sh
@@ -0,0 +1,41 @@
+#!/bin/sh
+set -eu
+
+readonly GitURL='https://git.causal.agency/src/tree/bin'
+
+src=$1
+man=${2:-}
+
+cat <<EOF
+<!DOCTYPE html>
+<title>${src}</title>
+<style>
+$(./scheme -st)
+html {
+	font-family: monospace;
+	color: var(--ansi17);
+	background-color: var(--ansi16);
+}
+a { color: var(--ansi4); }
+a:visited { color: var(--ansi5); }
+pre.hi {
+	-moz-tab-size: 4;
+	tab-size: 4;
+}
+.hi.Keyword { color: var(--ansi7); }
+.hi.Macro { color: var(--ansi2); }
+.hi.Tag { color: inherit; text-decoration: underline; }
+.hi.Tag:target { color: var(--ansi11); outline: none; }
+.hi.String { color: var(--ansi6); }
+.hi.Format { color: var(--ansi14); }
+.hi.Interp { color: var(--ansi3); }
+.hi.Comment { color: var(--ansi4); }
+.hi.Todo { color: var(--ansi12); }
+.hi.DiffOld { color: var(--ansi1); }
+.hi.DiffNew { color: var(--ansi2); }
+</style>
+<a href="${GitURL}/${src}">${src} in git</a>
+EOF
+
+[ -f "$man" ] && man -P cat "${PWD}/${man}" | ./ttpre
+./hi -t -f html -o anchor "$src"
diff --git a/bin/man1/beef.1 b/bin/man1/beef.1
new file mode 100644
index 00000000..ea52cfa0
--- /dev/null
+++ b/bin/man1/beef.1
@@ -0,0 +1,91 @@
+.Dd August 28, 2019
+.Dt BEEF 1
+.Os
+.
+.Sh NAME
+.Nm beef
+.Nd Befunge-93 interpreter
+.
+.Sh SYNOPSIS
+.Nm
+.Op Ar file
+.
+.Sh DESCRIPTION
+.Nm
+is a Befunge-93 interpreter.
+If no
+.Ar file
+is provided,
+the program is read from standard input.
+.
+.Ss Befunge-93 Command Summary
+.Bl -tag -width "0-9" -compact
+.It \(dq
+toggle string mode
+.It 0-9
+push value
+.It +
+add
+.It -
+subtract
+.It *
+multiply
+.It /
+divide
+.It %
+modulo
+.It !
+not
+.It `
+greater than
+.It >
+right
+.It <
+left
+.It ^
+up
+.It v
+down
+.It ?
+random
+.It _
+horizontal (left) if
+.It |
+vertical (up) if
+.It :
+duplicate
+.It \e
+swap
+.It $
+drop
+.It .
+output integer
+.It ,
+output ASCII
+.It #
+bridge
+.It g
+get (y, x)
+.It p
+put (y, x) = v
+.It &
+input integer
+.It ~
+input ASCII
+.It @
+exit
+.El
+.
+.Sh EXIT STATUS
+.Nm
+exits with the top value left on the stack,
+or 0 if the stack is left empty.
+.
+.Sh STANDARDS
+.Rs
+.%A Chris Pressey
+.%Q Cat's Eye Technologies
+.%T Befunge-93
+.%D September, 1993
+.%U https://github.com/catseye/Befunge-93/blob/master/doc/Befunge-93.markdown
+.Re
diff --git a/bin/man1/bibsort.1 b/bin/man1/bibsort.1
new file mode 100644
index 00000000..9d036920
--- /dev/null
+++ b/bin/man1/bibsort.1
@@ -0,0 +1,37 @@
+.Dd December 15, 2020
+.Dt BIBSORT 1
+.Os
+.
+.Sh NAME
+.Nm bibsort
+.Nd reformat bibliography
+.
+.Sh SYNOPSIS
+.Nm
+.Op Ar file
+.
+.Sh DESCRIPTION
+.Nm
+reformats on standard output
+the
+.Em STANDARDS
+section of the
+.Xr mdoc 7
+manual page
+.Ar file
+or standard input.
+Bibliographic references
+are sorted by author last names,
+and formatted in an item list
+with macro lines appearing
+in the order they are formatted by
+.Xr mandoc 1 .
+Additionally,
+.Ic \&%N
+macros referencing RFC numbers
+are rewritten to
+.Ic \&%R
+macros.
+.
+.Sh EXAMPLES
+.Dl :%!bibsort
diff --git a/bin/man1/bit.1 b/bin/man1/bit.1
new file mode 100644
index 00000000..b61bc704
--- /dev/null
+++ b/bin/man1/bit.1
@@ -0,0 +1,45 @@
+.Dd June 7, 2019
+.Dt BIT 1
+.Os
+.
+.Sh NAME
+.Nm bit
+.Nd a calculator
+.
+.Sh SYNOPSIS
+.Nm
+.
+.Sh DESCRIPTION
+.Nm
+is an integer calculator.
+Its syntax resembles that of C expressions,
+with the following changes:
+.
+.Bl -bullet
+.It
+Underscores are allowed in integer literals.
+.It
+The
+.Sy 0b
+prefix is used for binary literals.
+.It
+The
+.Sy ->
+operator is used for arithmetic shift.
+.It
+The postfix operators
+.Sy K ,
+.Sy M ,
+.Sy G ,
+.Sy T
+are used as constant multipliers.
+.It
+Single-letter (lower case) variables
+can be assigned.
+The variable
+.Sy _
+stores the previous result.
+.El
+.
+.Sh SEE ALSO
+.Xr operator 7
diff --git a/bin/man1/bri.1 b/bin/man1/bri.1
new file mode 100644
index 00000000..54a02322
--- /dev/null
+++ b/bin/man1/bri.1
@@ -0,0 +1,44 @@
+.Dd September 7, 2018
+.Dt BRI 1
+.Os
+.
+.Sh NAME
+.Nm bri
+.Nd backlight brightness control
+.
+.Sh SYNOPSIS
+.Nm
+.Op Ar brightness
+.Nm
+.Cm +
+.Nm
+.Cm -
+.
+.Sh DESCRIPTION
+.Nm
+controls the backlight brightness on Linux.
+.
+.Pp
+With no argument,
+the current brightness is printed.
+With a numerical
+.Ar brightness
+argument,
+the brightness is set.
+.
+.Pp
+The
+.Cm +
+and
+.Cm -
+arguments
+may be repeated any number of times
+and adjust the brightness
+in increments of 16.
+.
+.Sh FILES
+.Bl -tag
+.It Pa /sys/class/backlight
+Files under the first subdirectory found
+are used to control the backlight brightness.
+.El
diff --git a/bin/man1/c.1 b/bin/man1/c.1
new file mode 100644
index 00000000..3ae10945
--- /dev/null
+++ b/bin/man1/c.1
@@ -0,0 +1,40 @@
+.Dd May 31, 2020
+.Dt C 1
+.Os
+.
+.Sh NAME
+.Nm c
+.Nd run C
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl e Ar expr
+.Op Fl i Ar include
+.Op Ar stmts ...
+.
+.Sh DESCRIPTION
+The
+.Nm
+utility compiles and runs
+C statements wrapped in
+.Fn main
+with common includes.
+If no
+.Ar expr
+or
+.Ar stmts
+are provided,
+statements are read from standard input.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl e Ar expr
+Print the result of the C expression
+.Ar expr
+after executing
+.Ar stmts .
+.It Fl i Ar include
+Add the include file
+.Ar include .
+.El
diff --git a/bin/man1/dtch.1 b/bin/man1/dtch.1
new file mode 100644
index 00000000..e27713e1
--- /dev/null
+++ b/bin/man1/dtch.1
@@ -0,0 +1,67 @@
+.Dd August 12, 2019
+.Dt DTCH 1
+.Os
+.
+.Sh NAME
+.Nm dtch
+.Nd detached sessions
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl s
+.Ar name
+.Op Ar command ...
+.Nm
+.Fl a
+.Ar name
+.
+.Sh DESCRIPTION
+.Nm
+spawns a
+.Ar command
+in a detachable session.
+If no
+.Ar command
+is given,
+the value of
+.Ev SHELL
+is used.
+The
+.Nm
+process
+should be run as a background job
+or with
+.Xr nohup 1 .
+.
+.Pp
+To attach to an existing session,
+pass the
+.Fl a
+flag.
+To detach from the session,
+type
+.Ic ^Q .
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl a
+Attach to an existing session.
+.It Fl s
+Sink the output of
+.Ar command
+while detached.
+.El
+.
+.Sh FILES
+.Bl -tag -width Ds
+.It Pa ~/.dtch
+Directory of UNIX-domain sockets
+for each session.
+.El
+.
+.Sh EXAMPLES
+.Bd -literal -offset indent
+dtch foo vim &
+dtch -a foo
+.Ed
diff --git a/bin/man1/ever.1 b/bin/man1/ever.1
new file mode 100644
index 00000000..7689c5fb
--- /dev/null
+++ b/bin/man1/ever.1
@@ -0,0 +1,49 @@
+.Dd June  1, 2020
+.Dt EVER 1
+.Os
+.
+.Sh NAME
+.Nm ever
+.Nd watch files
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl i
+.Ar
+.Ar command
+.Nm
+.Op Fl i
+.Ar
+.Fl -
+.Ar command
+.Op Ar argument ...
+.
+.Sh DESCRIPTION
+.Nm
+executes the
+.Ar command
+whenever
+.Ar file
+is modified.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl i
+Attach the
+.Ar file
+which was modified
+to the standard input of
+.Ar command .
+.El
+.
+.Sh EXAMPLES
+.Dl ever ever.c make
+.Dl ever when.y ever.c -- make when ever
+.Dl ever -i ever.1 mandoc
+.
+.Sh CAVEATS
+.Nm
+does not support Linux
+since it uses
+.Xr kqueue 2 .
diff --git a/bin/man1/fbatt.1 b/bin/man1/fbatt.1
new file mode 100644
index 00000000..2d30cba7
--- /dev/null
+++ b/bin/man1/fbatt.1
@@ -0,0 +1,34 @@
+.Dd September 7, 2018
+.Dt FBATT 1
+.Os
+.
+.Sh NAME
+.Nm fbatt
+.Nd framebuffer battery indicator
+.
+.Sh SYNOPSIS
+.Nm
+.
+.Sh DESCRIPTION
+.Nm
+displays a battery charge indicator
+in the top-right corner
+of the Linux framebuffer.
+.
+.Sh ENVIRONMENT
+.Bl -tag
+.It Ev FRAMEBUFFER
+The framebuffer device path.
+.El
+.
+.Sh FILES
+.Bl -tag
+.It Pa /dev/fb0
+The default framebuffer device path.
+.It Pa /sys/class/power_supply
+The first subdirectory containing
+.Pa charge_full
+and
+.Pa charge_now
+is used to read the battery charge.
+.El
diff --git a/bin/man1/fbclock.1 b/bin/man1/fbclock.1
new file mode 100644
index 00000000..3195eb42
--- /dev/null
+++ b/bin/man1/fbclock.1
@@ -0,0 +1,36 @@
+.Dd September 7, 2018
+.Dt FBCLOCK 1
+.Os
+.
+.Sh NAME
+.Nm fbclock
+.Nd framebuffer clock
+.
+.Sh SYNOPSIS
+.Nm
+.
+.Sh DESCRIPTION
+.Nm
+displays a clock
+in the top-right corner
+of the Linux framebuffer.
+.
+.Sh ENVIRONMENT
+.Bl -tag
+.It Ev FONT
+Path to gzipped PSF file.
+.
+.It Ev FRAMEBUFFER
+The framebuffer device path.
+.El
+.
+.Sh FILES
+.Bl -tag
+.It Pa /dev/fb0
+The default framebuffer device path.
+.It Pa /usr/share/kbd/consolefonts/Lat2-Terminus16.psfu.gz
+The default font path.
+.El
+.
+.Sh SEE ALSO
+.Xr setfont 8
diff --git a/bin/man1/glitch.1 b/bin/man1/glitch.1
new file mode 100644
index 00000000..6562c4dc
--- /dev/null
+++ b/bin/man1/glitch.1
@@ -0,0 +1,77 @@
+.Dd September 7, 2018
+.Dt GLITCH 1
+.Os
+.
+.Sh NAME
+.Nm glitch
+.Nd PNG glitcher
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl cfimprxy
+.Op Fl a Ar filters
+.Op Fl d Ar filters
+.Op Fl o Ar file
+.Op Ar
+.
+.Sh DESCRIPTION
+.Nm
+misinterprets PNG files
+according to the options given
+to create natural glitch effects.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl a Ar filters
+Apply a pattern of comma-separated filters.
+Filters are
+.Cm none ,
+.Cm sub ,
+.Cm up ,
+.Cm average ,
+.Cm paeth .
+.
+.It Fl c
+Write to standard output.
+.
+.It Fl d Ar filters
+Declare a pattern of comma-separated filters.
+See
+.Fl a
+for list of filters.
+.
+.It Fl f
+Apply filtering in place of reconstruction.
+.
+.It Fl i
+Invert image data after filtering.
+.
+.It Fl m
+Mirror scanlines after filtering.
+.
+.It Fl o Ar file
+Write to
+.Ar file .
+.
+.It Fl p
+Use a broken Paeth predictor function.
+.
+.It Fl r
+Apply reconstruction in place of filtering.
+.
+.It Fl x
+Zero first pixel of each scanline after filtering.
+.
+.It Fl y
+Zero first scanline after filtering.
+.El
+.
+.Sh EXAMPLES
+.Dl glitch -m -a sub -d sub
+.
+.Sh SEE ALSO
+.Xr pngo 1
+.
+.Sh BUGS
+More wanted.
diff --git a/bin/man1/hi.1 b/bin/man1/hi.1
new file mode 100644
index 00000000..517fbab9
--- /dev/null
+++ b/bin/man1/hi.1
@@ -0,0 +1,173 @@
+.Dd December 15, 2019
+.Dt HI 1
+.Os
+.
+.Sh NAME
+.Nm hi
+.Nd syntax highlighter
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl t
+.Op Fl f Ar format
+.Op Fl l Ar lang
+.Op Fl n Ar name
+.Op Fl o Ar opts
+.Op Ar file
+.Nm
+.Fl c
+.
+.Sh DESCRIPTION
+.Nm
+highlights the contents of a
+.Ar file
+or standard input
+and formats it
+on standard output.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width "-f format"
+.It Fl c
+Compile all regular expressions and exit.
+.It Fl f Ar format
+Set the output format.
+.It Fl l Ar lang
+Set the input language.
+.It Fl n Ar name
+Override the name used
+to infer the input language.
+.It Fl o Ar opts
+Set output format options.
+.Ar opts
+is a comma-separated list of options.
+.It Fl t
+Default to
+.Cm text
+if the input language cannot be inferred.
+.El
+.
+.Ss Output Formats
+The default output format is
+.Cm ansi .
+.
+.Bl -tag -width Ds
+.It Cm ansi
+Output ANSI terminal escape codes.
+.
+.It Cm irc
+Output IRC formatting codes.
+.Pp
+The options are as follows:
+.Bl -tag -width "monospace"
+.It Cm monospace
+Use the monospace formatting code
+introduced by IRCCloud.
+.El
+.
+.It Cm html
+Output HTML
+.Sy <pre>
+with
+.Sy <span>
+classes.
+.
+.Pp
+The options are as follows:
+.Bl -tag -width "title=..."
+.It Cm anchor
+Output tags
+(top-level definition names)
+as anchor links.
+.
+.It Cm css Ns = Ns Ar url
+With
+.Cm document ,
+output a
+.Sy <link>
+element for the external stylesheet
+.Ar url .
+If unset,
+output default styles in a
+.Sy <style>
+element.
+.
+.It Cm document
+Output an HTML document.
+.
+.It Cm inline
+Output inline
+.Sy style
+attributes rather than classes.
+.
+.It Cm tab Ns = Ns Ar n
+With
+.Cm document
+or
+.Cm inline ,
+set the
+.Sy tab-size
+property to
+.Ar n .
+.
+.It Cm title Ns = Ns Ar ...
+With
+.Cm document ,
+set the
+.Sy <title>
+element text.
+The default title is the
+.Ar file
+name.
+.El
+.El
+.
+.Ss Input Languages
+If no input language is set with
+.Fl l ,
+it may be inferred from the name set by
+.Fl m
+or from the provided
+.Ar file
+name.
+.
+.Bl -tag -width Ds
+.It Cm c
+The C11 language.
+.
+.It Cm diff
+The output of
+.Xr diff 1
+with the
+.Fl u
+flag.
+.
+.It Cm make
+The portable subset of
+.Xr make 1 .
+Variable substitution supports
+one level of nesting with the same delimiter.
+.
+.It Cm mdoc
+The
+.Xr mdoc 7
+language.
+.
+.It Cm rust
+The Rust 2018 language.
+Nested raw strings and block comments
+are not highlighted correctly.
+.
+.It Cm sh
+The POSIX
+.Xr sh 1
+language.
+Here-documents are correctly highlighted
+only with a delimiter of
+.Ql EOF .
+Arbitrarily nested strings and command substitutions
+are not highlighted correctly.
+.
+.It Cm text
+Plain text.
+.El
diff --git a/bin/man1/hnel.1 b/bin/man1/hnel.1
new file mode 100644
index 00000000..82305be8
--- /dev/null
+++ b/bin/man1/hnel.1
@@ -0,0 +1,36 @@
+.Dd July 8, 2019
+.Dt HNEL 1
+.Os
+.
+.Sh NAME
+.Nm hnel
+.Nd PTY input remapper
+.
+.Sh SYNOPSIS
+.Nm
+.Ar string1
+.Ar string2
+.Ar command ...
+.
+.Sh DESCRIPTION
+.Nm
+runs the
+.Ar command
+in a new PTY,
+remapping input characters in
+.Ar string1
+to the corresponding characters in
+.Ar string2 .
+Type
+.Ic ^S
+to toggle remapping.
+.
+.Sh EXAMPLES
+.Dl hnel '[]{}' '{}[]' vim
+.
+.Sh SEE ALSO
+.Xr tr 1
+.
+.Sh BUGS
+Window size changes are not propagated
+to the child PTY.
diff --git a/bin/man1/modem.1 b/bin/man1/modem.1
new file mode 100644
index 00000000..a4bbc3f1
--- /dev/null
+++ b/bin/man1/modem.1
@@ -0,0 +1,31 @@
+.Dd December  8, 2020
+.Dt MODEM 1
+.Os
+.
+.Sh NAME
+.Nm modem
+.Nd fixed baud rate wrapper
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl r Ar rate
+.Ar command ...
+.
+.Sh DESCRIPTION
+.Nm
+runs the
+.Ar command
+in a new PTY
+with a fixed baud rate.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl r Ar rate
+Set the baud rate.
+The default is 19200.
+.El
+.
+.Sh BUGS
+Window size changes are not propagated
+to the child PTY.
diff --git a/bin/man1/nudge.1 b/bin/man1/nudge.1
new file mode 100644
index 00000000..3ca4294a
--- /dev/null
+++ b/bin/man1/nudge.1
@@ -0,0 +1,44 @@
+.Dd September  4, 2020
+.Dt NUDGE 1
+.Os
+.
+.Sh NAME
+.Nm nudge
+.Nd terminal vibrator
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl f Ar file
+.Op Fl n Ar count
+.Op Fl s Ar shake
+.Op Fl t Ar delay
+.
+.Sh DESCRIPTION
+The
+.Nm
+utility
+nudges the terminal.
+An
+.Xr xterm 1
+compatible terminal is required.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl f Ar file
+Open the terminal named by
+.Ar file .
+The default is
+.Pa /dev/tty .
+.It Fl n Ar count
+Set the number of times
+to nudge the terminal.
+The default is 2.
+.It Fl s Ar shake
+Set the shake intensity in pixels.
+The default is 10.
+.It Fl t Ar delay
+Set the interval between shakes
+in milliseconds.
+The default is 20.
+.El
diff --git a/bin/man1/order.1 b/bin/man1/order.1
new file mode 100644
index 00000000..8e0f9661
--- /dev/null
+++ b/bin/man1/order.1
@@ -0,0 +1,38 @@
+.Dd July 18, 2020
+.Dt ORDER 1
+.Os
+.
+.Sh NAME
+.Nm order
+.Nd operator precedence
+.
+.Sh SYNOPSIS
+.Nm
+.Op Ar expr ...
+.
+.Sh DESCRIPTION
+.Nm
+parses C expressions
+and prints them with parentheses
+according to the precedence rules in
+.Xr operator 7 .
+If no
+.Ar expr
+are given,
+each line of standard input
+is parsed and printed.
+.
+.Sh EXAMPLES
+.Bd -literal
+$ order 'a & b << 1'
+(a & (b << 1))
+.Ed
+.
+.Sh SEE ALSO
+.Xr operator 7
+.
+.Sh CAVEATS
+.Nm
+does not support the
+.Sy (type)
+operator.
diff --git a/bin/man1/pbd.1 b/bin/man1/pbd.1
new file mode 100644
index 00000000..bbc7b785
--- /dev/null
+++ b/bin/man1/pbd.1
@@ -0,0 +1,59 @@
+.Dd September 7, 2018
+.Dt PBD 1
+.Os
+.
+.Sh NAME
+.Nm pbd ,
+.Nm pbcopy ,
+.Nm pbpaste ,
+.Nm open
+.Nd macOS pasteboard daemon
+.
+.Sh SYNOPSIS
+.Nm
+.Nm pbcopy
+.Nm pbpaste
+.Nm open
+.Ar
+.
+.Sh DESCRIPTION
+.Nm
+is a daemon which pipes into macOS
+.Xr pbcopy 1 ,
+from
+.Xr pbpaste 1
+and invokes
+.Xr open 1
+in response to messages
+sent over TCP port 7062.
+.
+.Pp
+The socket can be forwarded through
+.Xr ssh 1
+and the stub implementations of
+.Nm pbcopy ,
+.Nm pbpaste
+and
+.Nm open
+can be used remotely
+to access the local pasteboard
+and open URLs.
+.
+.Pp
+Forwarding can be configured with:
+.Pp
+.Dl RemoteForward 7062 127.0.0.1:7062
+.
+.Sh EXAMPLES
+.Bd -literal -offset indent
+pbd &
+ssh -R 7062:127.0.0.1:7062 tux.local
+pbpaste
+.Ed
+.
+.Sh SEE ALSO
+.Xr open 1 ,
+.Xr pbcopy 1 ,
+.Xr pbpaste 1 ,
+.Xr ssh 1 ,
+.Xr ssh_config 5
diff --git a/bin/man1/pngo.1 b/bin/man1/pngo.1
new file mode 100644
index 00000000..cec13160
--- /dev/null
+++ b/bin/man1/pngo.1
@@ -0,0 +1,56 @@
+.Dd September 17, 2018
+.Dt PNGO 1
+.Os
+.
+.Sh NAME
+.Nm pngo
+.Nd PNG optimizer
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl cv
+.Op Fl o Ar file
+.Op Ar
+.
+.Sh DESCRIPTION
+.Nm
+optimizes PNG files for size.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl c
+Write to standard output.
+.It Fl o Ar file
+Write to
+.Ar file .
+.It Fl v
+Output PNG header information.
+.El
+.
+.Pp
+.Nm
+performs the following optimizations:
+.Bl -bullet
+.It
+Discard ancillary chunks.
+.It
+Discard unnecessary alpha channel.
+.It
+Convert unnecessary truecolor to grayscale.
+.It
+Palletize color and alpha if possible.
+.It
+Reduce bit depth if possible.
+.It
+Apply a simple filter heuristic.
+.It
+Apply zlib's best compresion.
+.El
+.
+.Sh SEE ALSO
+.Xr glitch 1
+.
+.Sh CAVEATS
+.Nm
+does not support interlaced PNGs.
diff --git a/bin/man1/psf2png.1 b/bin/man1/psf2png.1
new file mode 100644
index 00000000..db74c6e2
--- /dev/null
+++ b/bin/man1/psf2png.1
@@ -0,0 +1,53 @@
+.Dd September 28, 2018
+.Dt PSF2PNG 1
+.Os
+.
+.Sh NAME
+.Nm psf2png
+.Nd PSF2 to PNG renderer
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl b Ar bg
+.Op Fl c Ar cols
+.Op Fl f Ar fg
+.Op Fl s Ar str
+.Op Ar file
+.
+.Sh DESCRIPTION
+.Nm
+renders the PSF2 font
+.Ar file
+or standard input
+to PNG
+on standard output.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl b Ar bg
+Use
+.Ar bg
+(hexadecimal RGB)
+as background color.
+The default background color is black.
+.It Fl c Ar cols
+Arrange glyphs in
+.Ar cols
+columns.
+The default number of columns is 32.
+.It Fl f Ar fg
+Use
+.Ar fg
+(hexadecimal RGB)
+as foreground color.
+The default foreground color is white.
+.It Fl s Ar str
+Render glyphs for string
+.Ar str
+rather than all glyphs.
+.El
+.
+.Sh SEE ALSO
+.Xr pngo 1 ,
+.Xr psfed 1
diff --git a/bin/man1/psfed.1 b/bin/man1/psfed.1
new file mode 100644
index 00000000..3fbc4710
--- /dev/null
+++ b/bin/man1/psfed.1
@@ -0,0 +1,166 @@
+.Dd January 14, 2019
+.Dt PSFED 1
+.Os
+.
+.Sh NAME
+.Nm psfed
+.Nd PSF2 font editor
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl H Ar height
+.Op Fl g Ar glyphs
+.Op Fl h Ar height
+.Op Fl w Ar width
+.Ar file
+.
+.Sh DESCRIPTION
+.Nm
+is a PSF2 font editor
+for the Linux framebuffer.
+.
+.Pp
+The arguments are as follows:
+.
+.Bl -tag -width Ds
+.It Fl H Ar height
+Modify the height of an existing font.
+Only increasing the height is allowed.
+.
+.It Fl g Ar glyphs
+Set the number of glyphs in a new font.
+The default number of glyphs is 256.
+.
+.It Fl h Ar height
+Set the height of a new font.
+The default height is 16.
+.
+.It Fl w Ar width
+Set the width of a new font.
+The default width is 8.
+.El
+.
+.Ss Normal Mode
+In normal mode,
+each glyph is displayed in a grid.
+.
+.Pp
+.Bl -tag -width Ds -compact
+.It Ic q
+Quit.
+.Nm
+will ask for confirmation
+if the font has been modified
+since the last write.
+.
+.It Ic w
+Write font to
+.Ar file .
+.
+.It Ic - Ic +
+Adjust display scale.
+.
+.It Ic h Ic l
+Select previous/next glyph.
+.
+.It Ic k Ic j
+Select glyph in previous/next row.
+.
+.It Ic f
+Select glyph of next input character.
+.
+.It Ic '
+Return to previously selected glyph.
+.
+.It Ic y
+Copy selected glyph.
+.
+.It Ic e
+Edit selected glyph in
+.Sx Edit Mode .
+.
+.It Ic i
+Enter
+.Sx Preview Mode .
+.El
+.
+.Ss Edit Mode
+In edit mode,
+the selected glyph is displayed for editing
+surrounded by a checked border.
+The glyph is also displayed unscaled
+in the bottom-right corner.
+.
+.Pp
+.Bl -tag -width Ds -compact
+.It Ic ESC
+Return to
+.Sx Normal Mode .
+.
+.It Ic - Ic +
+Adjust display scale.
+.
+.It Ic g Ic G
+Toggle guide on selected column/row.
+.
+.It Ic h Ic l
+Select previous/next bit in row.
+.
+.It Ic k Ic j
+Select previous/next bit in column.
+.
+.It Ic SPACE
+Flip selected bit.
+.
+.It Ic r
+Invert glyph.
+.
+.It Ic H Ic L
+Move glyph left/right.
+.
+.It Ic K Ic J
+Move glyph up/down.
+.
+.It Ic p
+Paste the copied glyph.
+.
+.It Ic u
+Revert glyph to initial state.
+.El
+.
+.Ss Preview Mode
+In preview mode,
+arbitrary text may be entered
+for preview.
+Press
+.Ic ESC
+to return to
+.Sx Normal Mode .
+.
+.Sh ENVIRONMENT
+.Bl -tag -width FRAMEBUFFER
+.It Ev FRAMEBUFFER
+The framebuffer device path.
+The default path is
+.Pa /dev/fb0 .
+.El
+.
+.Sh SEE ALSO
+.Xr psfaddtable 1 ,
+.Xr psfgettable 1 ,
+.Xr psfstriptable 1 ,
+.Xr setfont 8
+.
+.Sh CAVEATS
+.Nm
+does not support Unicode tables.
+Use
+.Xr psfaddtable 1
+to add Unicode tables
+to fonts created by
+.Nm .
+.
+.Sh BUGS
+.Nm
+makes no attempt to convert header fields
+to and from little-endian format.
diff --git a/bin/man1/ptee.1 b/bin/man1/ptee.1
new file mode 100644
index 00000000..04f9cdac
--- /dev/null
+++ b/bin/man1/ptee.1
@@ -0,0 +1,40 @@
+.Dd July 17, 2019
+.Dt PTEE 1
+.Os
+.
+.Sh NAME
+.Nm ptee
+.Nd tee for PTYs
+.
+.Sh SYNOPSIS
+.Nm
+.Ar command ...
+.Cm >
+.Ar file
+.
+.Sh DESCRIPTION
+.Nm
+runs
+.Ar command
+in a new PTY
+which is mirrored to
+the current PTY
+and standard output.
+Standard output must be redirected
+to a file or pipe.
+.
+.Pp
+Type
+.Ic ^S
+to toggle writing to standard output.
+Type
+.Ic ^Q
+to write the media copy sequence for
+.Xr shotty 1 .
+.
+.Sh SEE ALSO
+.Xr tee 1
+.
+.Sh BUGS
+Window size changes are not propagated
+to the child PTY.
diff --git a/bin/man1/relay.1 b/bin/man1/relay.1
new file mode 100644
index 00000000..402c4726
--- /dev/null
+++ b/bin/man1/relay.1
@@ -0,0 +1,48 @@
+.Dd April 28, 2019
+.Dt RELAY 1
+.Os
+.
+.Sh NAME
+.Nm relay
+.Nd IRC relay bot
+.
+.Sh SYNOPSIS
+.Nm
+.Ar host
+.Ar port
+.Ar nick
+.Ar chan
+.
+.Sh DESCRIPTION
+.Nm
+is one half of an IRC relay pair.
+It connects to
+.Ar host Ns : Ns Ar port
+over TLS
+as
+.Ar nick
+and joins
+.Ar chan .
+.
+.Pp
+.Nm
+outputs messages from
+.Ar chan
+to standard output
+and sends messages to
+.Ar chan
+from standard input.
+Two
+.Nm
+processes can be connected with
+.Xr mkfifo 1 .
+.
+.Sh EXAMPLES
+.Bd -literal -offset indent
+mkfifo a b
+relay a.example.com 6697 relay '#example' <>a >b
+relay b.example.com 6697 relay '#example' <>b >a
+.Ed
+.
+.Sh SEE ALSO
+.Xr mkfifo 1
diff --git a/bin/man1/scheme.1 b/bin/man1/scheme.1
new file mode 100644
index 00000000..9aa4f054
--- /dev/null
+++ b/bin/man1/scheme.1
@@ -0,0 +1,56 @@
+.Dd July 6, 2019
+.Dt SCHEME 1
+.Os
+.
+.Sh NAME
+.Nm scheme
+.Nd color scheme
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl acghilmstx
+.Op Fl p Ar n
+.
+.Sh DESCRIPTION
+.Nm
+generates a color scheme
+and outputs it in a number of formats.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl a
+Generate the 16 ANSI colors.
+This is the default.
+.It Fl c
+Output a C enum.
+.It Fl g
+Output a swatch PNG.
+.It Fl h
+Output floating point HSV.
+.It Fl i
+Swap black and white.
+.It Fl l
+Output Linux console OSC sequences.
+.It Fl m
+Output a
+.Xr mintty 1
+theme.
+Use with
+.Fl t .
+.It Fl p Ar n
+Generate only the color
+.Ar n .
+.It Fl s
+Output CSS
+for classes named
+.Sy fg Ns Ar n
+and
+.Sy bg Ns Ar n .
+.It Fl t
+Generate the 16 ANSI colors as well as
+background, foreground, bold, selection and cursor colors.
+.It Fl x
+Output hexadecimal RGB.
+This is the default.
+.El
diff --git a/bin/man1/shotty.1 b/bin/man1/shotty.1
new file mode 100644
index 00000000..d5eaa780
--- /dev/null
+++ b/bin/man1/shotty.1
@@ -0,0 +1,92 @@
+.Dd November 25, 2019
+.Dt SHOTTY 1
+.Os
+.
+.Sh NAME
+.Nm shotty
+.Nd terminal capture
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl Bdns
+.Op Fl b Ar bg
+.Op Fl f Ar fg
+.Op Fl h Ar rows
+.Op Fl w Ar cols
+.Op Ar file
+.
+.Sh DESCRIPTION
+.Nm
+interprets terminal output from
+.Ar file
+or standard input
+and produces HTML
+.Sy <pre>
+on standard output.
+.
+.Pp
+Terminal output
+can be captured with
+.Xr ptee 1 .
+.Nm
+targets compatibility with
+.Ev TERM Ns = Ns Cm xterm
+and
+.Ev TERM Ns = Ns Cm xterm-256color
+as used by
+.Xr ncurses 3 .
+A snapshot of the terminal
+is output each time
+a media copy sequence occurs,
+or once at the end of the capture.
+.
+.Pp
+HTML output uses the classes
+.Sy bg Ns Va n
+and
+.Sy fg Ns Va n ,
+and inline styles for
+bold, italic and underline.
+CSS for colors can be generated with
+.Xr scheme 1 .
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width "-w cols"
+.It Fl B
+Replace bold with bright colors.
+.
+.It Fl b Ar bg
+Set the default background color.
+The default value is 0 (black).
+.
+.It Fl d
+Output the terminal state
+following each control sequence.
+.
+.It Fl f Ar fg
+Set the default foreground color.
+The default value is 7 (white).
+.
+.It Fl h Ar rows
+Set the terminal height.
+The default value is 24.
+.
+.It Fl n
+Do not show the cursor.
+.
+.It Fl s
+Set the terminal size
+from the current terminal size.
+.
+.It Fl w Ar cols
+Set the terminal width.
+The default value is 80.
+.El
+.
+.Sh EXAMPLES
+.Dl ptee htop | shotty -s > htop.html
+.
+.Sh SEE ALSO
+.Xr ptee 1 ,
+.Xr scheme 1
diff --git a/bin/man1/title.1 b/bin/man1/title.1
new file mode 100644
index 00000000..43ecc5e2
--- /dev/null
+++ b/bin/man1/title.1
@@ -0,0 +1,51 @@
+.Dd September 10, 2019
+.Dt TITLE 1
+.Os
+.
+.Sh NAME
+.Nm title
+.Nd page titles
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl v
+.Op Fl x Ar pattern
+.Op Ar url
+.
+.Sh DESCRIPTION
+.Nm
+fetches HTML page titles
+over HTTP and HTTPS.
+.Nm
+scans standard input for URLs
+and writes their titles to standard output.
+If a
+.Ar url
+argument is given,
+.Nm
+exits after fetching its title.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl x Ar pattern
+Exclude URLs matching
+.Ar pattern ,
+which is a modern regular expression.
+See
+.Xr re_format 7 .
+.It Fl v
+Enable
+.Xr libcurl 3
+verbose output.
+.El
+.
+.Sh EXAMPLES
+.Bd -literal -offset indent
+mkfifo snarf titles
+relay irc.example.org 6697 snarf '#example' <>titles >snarf
+title <snarf >titles
+.Ed
+.
+.Sh SEE ALSO
+.Xr relay 1
diff --git a/bin/man1/ttpre.1 b/bin/man1/ttpre.1
new file mode 100644
index 00000000..bd178525
--- /dev/null
+++ b/bin/man1/ttpre.1
@@ -0,0 +1,32 @@
+.Dd October 8, 2018
+.Dt TTPRE 1
+.Os
+.
+.Sh NAME
+.Nm ttpre
+.Nd man output to HTML
+.
+.Sh SYNOPSIS
+.Nm
+.
+.Sh DESCRIPTION
+.Nm
+formats
+.Xr man 1
+output on standard input
+as an HTML
+.Sy <pre>
+fragment on standard output.
+Ampersands and angle brackets
+are replaced with corresponding HTML entities,
+and backspace formatting sequences
+are replaced with
+.Sy <i>
+and
+.Sy <b>
+tags.
+.
+.Sh SEE ALSO
+.Xr less 1 ,
+.Xr man 1 ,
+.Xr mandoc 1
diff --git a/bin/man1/up.1 b/bin/man1/up.1
new file mode 100644
index 00000000..58b5359f
--- /dev/null
+++ b/bin/man1/up.1
@@ -0,0 +1,76 @@
+.Dd July 15, 2019
+.Dt UP 1
+.Os
+.
+.Sh NAME
+.Nm up
+.Nd upload file
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl h
+.Op Ar file
+.
+.Nm
+.Fl c | t
+.Ar command ...
+.
+.Nm
+.Fl s
+.
+.Sh DESCRIPTION
+.Nm
+uploads a file
+to temp.causal.agency with
+.Xr scp 1 .
+If no
+.Ar file
+is provided,
+standard input is read
+and uploaded as text.
+.
+.Pp
+The destination file name
+is chosen using
+.Xr date 1
+and
+.Xr openssl 1
+.Cm rand .
+The URL of the uploaded file is printed
+and copied to the pasteboard with
+.Xr pbcopy 1
+if available.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl c
+Run a command
+to produce a text file for upload.
+.It Fl h
+Use
+.Xr hi 1
+to produce an HTML file for upload.
+.It Fl s
+Use
+.Xr screencapture 1
+to produce a PNG file for upload.
+The file is optimized by
+.Xr pngo 1
+if available.
+.It Fl t
+Run a command with
+.Xr ptee 1
+and
+.Xr shotty 1
+to produce an HTML file for upload.
+.El
+.
+.Pp
+Any arguments after
+.Ql \-\-
+are passed to
+.Xr hi 1
+and
+.Xr screencapture 1 ,
+respectively.
diff --git a/bin/man1/when.1 b/bin/man1/when.1
new file mode 100644
index 00000000..0b473573
--- /dev/null
+++ b/bin/man1/when.1
@@ -0,0 +1,76 @@
+.Dd July 24, 2019
+.Dt WHEN 1
+.Os
+.
+.Sh NAME
+.Nm when
+.Nd date calculator
+.
+.Sh SYNOPSIS
+.Nm
+.Op Ar expr
+.
+.Sh DESCRIPTION
+.Nm
+is a date calculator.
+If no
+.Ar expr
+is given,
+expressions are read
+from standard input.
+.
+.Pp
+The grammar is as follows:
+.Bl -tag -width Ds
+.It Sy \&.
+Today's date.
+.
+.It Ar month Ar date Op Ar year
+A full date,
+or a date in the current year.
+.Ar month
+must be at least three letters.
+.
+.It Ar day
+A day of the week
+in the current week.
+.Ar day
+must be at least three letters.
+.
+.It Sy < Ar date
+The date one week before.
+.
+.It Sy > Ar date
+The date one week after.
+.
+.It Ar date Sy + Ar interval
+The date after some interval.
+.
+.It Ar date Sy - Ar interval
+The date before some interval.
+.
+.It Ar date Sy - Ar date
+The interval between two dates.
+.
+.It Ar num Sy d
+A number of days.
+.
+.It Ar num Sy w
+A number of weeks.
+.
+.It Ar num Sy m
+A number of months.
+.
+.It Ar num Sy y
+A number of years.
+.El
+.
+.Sh EXAMPLES
+.Bl -tag -width "Dec 25 - ."
+.It Ic Dec 25 - \&.
+How long until Christmas.
+.It Ic >Fri
+The date next Friday.
+.It Ic \&. + 2w
+Your last day at work.
+.El
diff --git a/bin/man1/xx.1 b/bin/man1/xx.1
new file mode 100644
index 00000000..d38789a7
--- /dev/null
+++ b/bin/man1/xx.1
@@ -0,0 +1,68 @@
+.Dd September 7, 2018
+.Dt XX 1
+.Os
+.
+.Sh NAME
+.Nm xx
+.Nd hexdump
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl arsz
+.Op Fl c Ar cols
+.Op Fl g Ar group
+.Op Fl p Ar count
+.Op Ar file
+.
+.Sh DESCRIPTION
+.Nm
+dumps the contents of a
+.Ar file
+or standard input
+in hexadecimal format.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl a
+Toggle ASCII output.
+.
+.It Fl c Ar cols
+Output
+.Ar cols
+bytes per line.
+The default
+.Ar cols
+is 16.
+.
+.It Fl g Ar group
+Output extra space after every
+.Ar group
+bytes.
+The default
+.Ar group
+is 8.
+.
+.It Fl p Ar count
+Output a blank line after every
+.Ar count
+bytes.
+.Ar count
+must be a multiple of
+.Ar cols .
+.
+.It Fl r
+Reverse hexdump.
+Read hexadecimal input
+and write byte output.
+.
+.It Fl s
+Toggle offset output.
+.
+.It Fl z
+Skip output of lines containing only zeros.
+.El
+.
+.Sh SEE ALSO
+.Xr hexdump 1 ,
+.Xr xxd 1
diff --git a/bin/man3/png.3 b/bin/man3/png.3
new file mode 100644
index 00000000..accffbd7
--- /dev/null
+++ b/bin/man3/png.3
@@ -0,0 +1,90 @@
+.Dd July 25, 2019
+.Dt PNG 3
+.Os
+.
+.Sh NAME
+.Nm png
+.Nd basic PNG output
+.
+.Sh SYNOPSIS
+.In png.h
+.
+.Ft void
+.Fo pngHead
+.Fa "FILE *file"
+.Fa "uint32_t width"
+.Fa "uint32_t height"
+.Fa "uint8_t depth"
+.Fa "uint8_t color"
+.Fc
+.
+.Ft void
+.Fn pngPalette "FILE *file" "const uint8_t *pal" "uint32_t len"
+.
+.Ft void
+.Fn pngData "FILE *file" "const uint8_t *data" "uint32_t len"
+.
+.Ft void
+.Fn pngTail "FILE *file"
+.
+.Sh DESCRIPTION
+The
+.Fn pngHead
+function
+writes the
+.Sy IHDR
+chunk to
+.Fa file .
+The
+.Fa color
+parameter can be one of
+.Dv PNGGrayscale ,
+.Dv PNGTruecolor
+optionally
+.Em or Ns 'ed
+with
+.Dv PNGAlpha ,
+or
+.Dv PNGIndexed .
+.
+.Pp
+The
+.Fn pngPalette
+function
+writes the
+.Sy PLTE
+chunk to
+.Fa file .
+.
+.Pp
+The
+.Fn pngData
+function
+writes the
+.Sy IDAT
+chunk to
+.Fa file
+without compression.
+The constants
+.Dv PNGNone ,
+.Dv PNGSub ,
+.Dv PNGUp ,
+.Dv PNGAverage ,
+.Dv PNGPaeth
+are defined
+for use in PNG data.
+.
+.Pp
+The
+.Fn pngTail
+function
+writes the
+.Sy IEND
+chunk to
+.Fa file .
+.
+.Sh ERRORS
+Any errors from writing to
+.Fa file
+are handled by calling
+.Xr err 3 .
diff --git a/bin/modem.c b/bin/modem.c
new file mode 100644
index 00000000..2133ae08
--- /dev/null
+++ b/bin/modem.c
@@ -0,0 +1,102 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+
+#if defined __FreeBSD__
+#include <libutil.h>
+#elif defined __linux__
+#include <pty.h>
+#else
+#include <util.h>
+#endif
+
+typedef unsigned uint;
+typedef unsigned char byte;
+
+static struct termios saveTerm;
+static void restoreTerm(void) {
+	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+
+	uint baudRate = 19200;
+	for (int opt; 0 < (opt = getopt(argc, argv, "r:"));) {
+		switch (opt) {
+			break; case 'r': baudRate = strtoul(optarg, NULL, 10);
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (argc - optind < 1) return EX_USAGE;
+
+	error = tcgetattr(STDIN_FILENO, &saveTerm);
+	if (error) err(EX_IOERR, "tcgetattr");
+	atexit(restoreTerm);
+
+	struct termios raw = saveTerm;
+	cfmakeraw(&raw);
+	error = tcsetattr(STDIN_FILENO, TCSADRAIN, &raw);
+	if (error) err(EX_IOERR, "tcsetattr");
+
+	struct winsize window;
+	error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window);
+	if (error) err(EX_IOERR, "TIOCGWINSZ");
+
+	int pty;
+	pid_t pid = forkpty(&pty, NULL, NULL, &window);
+	if (pid < 0) err(EX_OSERR, "forkpty");
+
+	if (!pid) {
+		execvp(argv[optind], &argv[optind]);
+		err(EX_NOINPUT, "%s", argv[optind]);
+	}
+
+	byte c;
+	struct pollfd fds[2] = {
+		{ .events = POLLIN, .fd = STDIN_FILENO },
+		{ .events = POLLIN, .fd = pty },
+	};
+	while (usleep(8 * 1000000 / baudRate), 0 < poll(fds, 2, -1)) {
+		if (fds[0].revents) {
+			ssize_t size = read(STDIN_FILENO, &c, 1);
+			if (size < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
+			size = write(pty, &c, 1);
+			if (size < 0) err(EX_IOERR, "write(%d)", pty);
+		}
+
+		if (fds[1].revents) {
+			ssize_t size = read(pty, &c, 1);
+			if (size < 0) err(EX_IOERR, "read(%d)", pty);
+			if (!size) break;
+			size = write(STDOUT_FILENO, &c, 1);
+			if (size < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
+		}
+	}
+
+	int status;
+	pid_t dead = waitpid(pid, &status, 0);
+	if (dead < 0) err(EX_OSERR, "waitpid");
+	return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
+}
diff --git a/bin/nudge.c b/bin/nudge.c
new file mode 100644
index 00000000..108d2459
--- /dev/null
+++ b/bin/nudge.c
@@ -0,0 +1,78 @@
+/* Copyright (C) 2020  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+
+static int shake = 10;
+static int delay = 20000;
+static int count = 2;
+
+static void move(int tty, int x, int y) {
+	dprintf(tty, "\33[3;%d;%dt", x, y);
+	usleep(delay);
+}
+
+int main(int argc, char *argv[]) {
+	const char *path = "/dev/tty";
+	for (int opt; 0 < (opt = getopt(argc, argv, "f:n:s:t:"));) {
+		switch (opt) {
+			break; case 'f': path = optarg;
+			break; case 'n': count = atoi(optarg);
+			break; case 's': shake = atoi(optarg);
+			break; case 't': delay = atoi(optarg) * 1000;
+			break; default:  return EX_USAGE;
+		}
+	}
+
+	int tty = open(path, O_RDWR);
+	if (tty < 0) err(EX_OSFILE, "%s", path);
+
+	struct termios save;
+	int error = tcgetattr(tty, &save);
+	if (error) err(EX_IOERR, "tcgetattr");
+
+	struct termios raw = save;
+	cfmakeraw(&raw);
+	error = tcsetattr(tty, TCSAFLUSH, &raw);
+	if (error) err(EX_IOERR, "tcsetattr");
+
+	char buf[256];
+	dprintf(tty, "\33[13t");
+	ssize_t len = read(tty, buf, sizeof(buf) - 1);
+	buf[(len < 0 ? 0 : len)] = '\0';
+
+	int x, y;
+	int n = sscanf(buf, "\33[3;%d;%dt", &x, &y);
+
+	error = tcsetattr(tty, TCSANOW, &save);
+	if (error) err(EX_IOERR, "tcsetattr");
+	if (n < 2) return EX_CONFIG;
+
+	dprintf(tty, "\33[5t");
+	for (int i = 0; i < count; ++i) {
+		move(tty, x - shake, y);
+		move(tty, x, y + shake);
+		move(tty, x + shake, y);
+		move(tty, x, y - shake);
+		move(tty, x, y);
+	}
+}
diff --git a/bin/order.y b/bin/order.y
new file mode 100644
index 00000000..b798e634
--- /dev/null
+++ b/bin/order.y
@@ -0,0 +1,193 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+%{
+
+#include <ctype.h>
+#include <err.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+
+int vasprintf(char **ret, const char *format, va_list ap);
+
+static void yyerror(const char *str) {
+	errx(EX_DATAERR, "%s", str);
+}
+
+#define YYSTYPE char *
+
+static char *fmt(const char *format, ...) {
+	char *str = NULL;
+	va_list ap;
+	va_start(ap, format);
+	vasprintf(&str, format, ap);
+	va_end(ap);
+	if (!str) err(EX_OSERR, "vasprintf");
+	return str;
+}
+
+static int yylex(void);
+
+%}
+
+%left ','
+%right '=' MulAss DivAss ModAss AddAss SubAss ShlAss ShrAss AndAss XorAss OrAss
+%right '?' ':'
+%left Or
+%left And
+%left '|'
+%left '^'
+%left '&'
+%left Eq Ne
+%left '<' Le '>' Ge
+%left Shl Shr
+%left '+' '-'
+%left '*' '/' '%'
+%right '!' '~' Inc Dec Sizeof
+%left '(' ')' '[' ']' Arr '.'
+
+%token Var
+
+%%
+
+start:
+	expr { printf("%s\n", $1); }
+	;
+
+expr:
+	Var
+	| '(' expr ')' { $$ = $2; }
+	| expr '[' expr ']' { $$ = fmt("(%s[%s])", $1, $3); }
+	| expr Arr Var { $$ = fmt("(%s->%s)", $1, $3); }
+	| expr '.' Var { $$ = fmt("(%s.%s)", $1, $3); }
+	| '!' expr { $$ = fmt("(!%s)", $2); }
+	| '~' expr { $$ = fmt("(~%s)", $2); }
+	| Inc expr { $$ = fmt("(++%s)", $2); }
+	| Dec expr { $$ = fmt("(--%s)", $2); }
+	| expr Inc { $$ = fmt("(%s++)", $1); }
+	| expr Dec { $$ = fmt("(%s--)", $1); }
+	| '-' expr %prec '!' { $$ = fmt("(-%s)", $2); }
+	| '*' expr %prec '!' { $$ = fmt("(*%s)", $2); }
+	| '&' expr %prec '!' { $$ = fmt("(&%s)", $2); }
+	| Sizeof expr { $$ = fmt("(sizeof %s)", $2); }
+	| expr '*' expr { $$ = fmt("(%s * %s)", $1, $3); }
+	| expr '/' expr { $$ = fmt("(%s / %s)", $1, $3); }
+	| expr '%' expr { $$ = fmt("(%s %% %s)", $1, $3); }
+	| expr '+' expr { $$ = fmt("(%s + %s)", $1, $3); }
+	| expr '-' expr { $$ = fmt("(%s - %s)", $1, $3); }
+	| expr Shl expr { $$ = fmt("(%s << %s)", $1, $3); }
+	| expr Shr expr { $$ = fmt("(%s >> %s)", $1, $3); }
+	| expr '<' expr { $$ = fmt("(%s < %s)", $1, $3); }
+	| expr Le expr { $$ = fmt("(%s <= %s)", $1, $3); }
+	| expr '>' expr { $$ = fmt("(%s > %s)", $1, $3); }
+	| expr Ge expr { $$ = fmt("(%s >= %s)", $1, $3); }
+	| expr Eq expr { $$ = fmt("(%s == %s)", $1, $3); }
+	| expr Ne expr { $$ = fmt("(%s != %s)", $1, $3); }
+	| expr '&' expr { $$ = fmt("(%s & %s)", $1, $3); }
+	| expr '^' expr { $$ = fmt("(%s ^ %s)", $1, $3); }
+	| expr '|' expr { $$ = fmt("(%s | %s)", $1, $3); }
+	| expr And expr { $$ = fmt("(%s && %s)", $1, $3); }
+	| expr Or expr { $$ = fmt("(%s || %s)", $1, $3); }
+	| expr '?' expr ':' expr { $$ = fmt("(%s ? %s : %s)", $1, $3, $5); }
+	| expr ass expr %prec '=' { $$ = fmt("(%s %s %s)", $1, $2, $3); }
+	| expr ',' expr { $$ = fmt("(%s, %s)", $1, $3); }
+	;
+
+ass:
+	'=' { $$ = "="; }
+	| MulAss { $$ = "*="; }
+	| DivAss { $$ = "/="; }
+	| ModAss { $$ = "%="; }
+	| AddAss { $$ = "+="; }
+	| SubAss { $$ = "-="; }
+	| ShlAss { $$ = "<<="; }
+	| ShrAss { $$ = ">>="; }
+	| AndAss { $$ = "&="; }
+	| XorAss { $$ = "^="; }
+	| OrAss { $$ = "|="; }
+	;
+
+%%
+
+#define T(a, b) ((int)(a) << 8 | (int)(b))
+
+static const char *input;
+
+static int yylex(void) {
+	while (isspace(input[0])) input++;
+	if (!input[0]) return EOF;
+
+	int len;
+	for (len = 0; isalnum(input[len]) || input[len] == '_'; ++len);
+	if (len) {
+		if (!strncmp(input, "sizeof", len)) {
+			input += len;
+			return Sizeof;
+		}
+		yylval = fmt("%.*s", len, input);
+		input += len;
+		return Var;
+	}
+
+	int tok;
+	switch (T(input[0], input[1])) {
+		break; case T('-', '>'): tok = Arr;
+		break; case T('+', '+'): tok = Inc;
+		break; case T('-', '-'): tok = Dec;
+		break; case T('<', '<'): tok = Shl;
+		break; case T('>', '>'): tok = Shr;
+		break; case T('<', '='): tok = Le;
+		break; case T('>', '='): tok = Ge;
+		break; case T('=', '='): tok = Eq;
+		break; case T('!', '='): tok = Ne;
+		break; case T('&', '&'): tok = And;
+		break; case T('|', '|'): tok = Or;
+		break; case T('*', '='): tok = MulAss;
+		break; case T('/', '='): tok = DivAss;
+		break; case T('%', '='): tok = ModAss;
+		break; case T('+', '='): tok = AddAss;
+		break; case T('-', '='): tok = SubAss;
+		break; case T('&', '='): tok = AndAss;
+		break; case T('^', '='): tok = XorAss;
+		break; case T('|', '='): tok = OrAss;
+		break; default: return *input++;
+	}
+	input += 2;
+
+	switch (T(tok, input[0])) {
+		case T(Shl, '='): input++; return ShlAss;
+		case T(Shr, '='): input++; return ShrAss;
+	}
+
+	return tok;
+}
+
+int main(int argc, char *argv[]) {
+	for (int i = 1; i < argc; ++i) {
+		input = argv[i];
+		yyparse();
+	}
+	if (argc > 1) return EX_OK;
+	size_t cap = 0;
+	char *buf = NULL;
+	while (0 < getline(&buf, &cap, stdin)) {
+		input = buf;
+		yyparse();
+	}
+}
diff --git a/bin/pbd.c b/bin/pbd.c
new file mode 100644
index 00000000..2ba333fd
--- /dev/null
+++ b/bin/pbd.c
@@ -0,0 +1,152 @@
+/* Copyright (C) 2017  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <fcntl.h>
+#include <netinet/in.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+typedef unsigned char byte;
+
+static void spawn(const char *cmd, const char *arg, int dest, int src) {
+	pid_t pid = fork();
+	if (pid < 0) err(EX_OSERR, "fork");
+
+	if (pid) {
+		int status;
+		pid_t dead = waitpid(pid, &status, 0);
+		if (dead < 0) err(EX_OSERR, "waitpid(%d)", pid);
+		if (status) warnx("%s: status %d", cmd, status);
+
+	} else {
+		int fd = dup2(src, dest);
+		if (fd < 0) err(EX_OSERR, "dup2");
+
+		execlp(cmd, cmd, arg, NULL);
+		err(EX_UNAVAILABLE, "%s", cmd);
+	}
+}
+
+static int pbd(void) {
+	int error;
+
+	int server = socket(PF_INET, SOCK_STREAM, 0);
+	if (server < 0) err(EX_OSERR, "socket");
+
+	error = fcntl(server, F_SETFD, FD_CLOEXEC);
+	if (error) err(EX_IOERR, "fcntl");
+
+	struct sockaddr_in addr = {
+		.sin_family = AF_INET,
+		.sin_port = htons(7062),
+		.sin_addr = { .s_addr = htonl(0x7F000001) },
+	};
+	error = bind(server, (struct sockaddr *)&addr, sizeof(addr));
+	if (error) err(EX_UNAVAILABLE, "bind");
+
+	error = listen(server, 0);
+	if (error) err(EX_UNAVAILABLE, "listen");
+
+	for (;;) {
+		int client = accept(server, NULL, NULL);
+		if (client < 0) err(EX_IOERR, "accept");
+
+		error = fcntl(client, F_SETFD, FD_CLOEXEC);
+		if (error) err(EX_IOERR, "fcntl");
+
+		char c = 0;
+		ssize_t size = read(client, &c, 1);
+		if (size < 0) warn("read");
+
+		switch (c) {
+			break; case 'p': spawn("pbpaste", NULL, STDOUT_FILENO, client);
+			break; case 'c': spawn("pbcopy", NULL, STDIN_FILENO, client);
+			break; case 'o': spawn("xargs", "open", STDIN_FILENO, client);
+		}
+
+		close(client);
+	}
+}
+
+static int pbdClient(char c) {
+	int client = socket(PF_INET, SOCK_STREAM, 0);
+	if (client < 0) err(EX_OSERR, "socket");
+
+	struct sockaddr_in addr = {
+		.sin_family = AF_INET,
+		.sin_port = htons(7062),
+		.sin_addr = { .s_addr = htonl(0x7F000001) },
+	};
+	int error = connect(client, (struct sockaddr *)&addr, sizeof(addr));
+	if (error) err(EX_UNAVAILABLE, "connect");
+
+	ssize_t size = write(client, &c, 1);
+	if (size < 0) err(EX_IOERR, "write");
+
+	return client;
+}
+
+static void copy(int out, int in) {
+	byte buf[4096];
+	ssize_t readSize;
+	while (0 < (readSize = read(in, buf, sizeof(buf)))) {
+		ssize_t writeSize = write(out, buf, readSize);
+		if (writeSize < 0) err(EX_IOERR, "write(%d)", out);
+	}
+	if (readSize < 0) err(EX_IOERR, "read(%d)", in);
+}
+
+static int pbcopy(void) {
+	int client = pbdClient('c');
+	copy(client, STDIN_FILENO);
+	return EX_OK;
+}
+
+static int pbpaste(void) {
+	int client = pbdClient('p');
+	copy(STDOUT_FILENO, client);
+	return EX_OK;
+}
+
+static int open1(const char *url) {
+	if (!url) return EX_USAGE;
+	int client = pbdClient('o');
+	ssize_t size = write(client, url, strlen(url));
+	if (size < 0) err(EX_IOERR, "write");
+	return EX_OK;
+}
+
+int main(int argc, char *argv[]) {
+	(void)argc;
+	if (strchr(argv[0], '/')) {
+		argv[0] = strrchr(argv[0], '/') + 1;
+	}
+	switch (argv[0][0] && argv[0][1] ? argv[0][2] : 0) {
+		case 'd': return pbd();
+		case 'c': return pbcopy();
+		case 'p': return pbpaste();
+		case 'e': return open1(argv[1]);
+		default:  return EX_USAGE;
+	}
+}
diff --git a/bin/png.h b/bin/png.h
new file mode 100644
index 00000000..15b6d13d
--- /dev/null
+++ b/bin/png.h
@@ -0,0 +1,108 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+
+static inline uint32_t pngCRCTable(uint8_t n) {
+	static uint32_t table[256];
+	if (table[1]) return table[n];
+	for (int i = 0; i < 256; ++i) {
+		table[i] = i;
+		for (int j = 0; j < 8; ++j) {
+			table[i] = (table[i] >> 1) ^ (table[i] & 1 ? 0xEDB88320 : 0);
+		}
+	}
+	return table[n];
+}
+
+static uint32_t pngCRC;
+
+static inline void pngWrite(FILE *file, const uint8_t *ptr, uint32_t len) {
+	if (!fwrite(ptr, len, 1, file)) err(EX_IOERR, "pngWrite");
+	for (uint32_t i = 0; i < len; ++i) {
+		pngCRC = pngCRCTable(pngCRC ^ ptr[i]) ^ (pngCRC >> 8);
+	}
+}
+static inline void pngInt32(FILE *file, uint32_t n) {
+	pngWrite(file, (uint8_t []) { n >> 24, n >> 16, n >> 8, n }, 4);
+}
+static inline void pngChunk(FILE *file, char type[static 4], uint32_t len) {
+	pngInt32(file, len);
+	pngCRC = ~0;
+	pngWrite(file, (uint8_t *)type, 4);
+}
+
+enum {
+	PNGGrayscale,
+	PNGTruecolor = 2,
+	PNGIndexed,
+	PNGAlpha,
+};
+
+static inline void pngHead(
+	FILE *file, uint32_t width, uint32_t height, uint8_t depth, uint8_t color
+) {
+	pngWrite(file, (uint8_t *)"\x89PNG\r\n\x1A\n", 8);
+	pngChunk(file, "IHDR", 13);
+	pngInt32(file, width);
+	pngInt32(file, height);
+	pngWrite(file, &depth, 1);
+	pngWrite(file, &color, 1);
+	pngWrite(file, (uint8_t []) { 0, 0, 0 }, 3);
+	pngInt32(file, ~pngCRC);
+}
+
+static inline void pngPalette(FILE *file, const uint8_t *pal, uint32_t len) {
+	pngChunk(file, "PLTE", len);
+	pngWrite(file, pal, len);
+	pngInt32(file, ~pngCRC);
+}
+
+enum {
+	PNGNone,
+	PNGSub,
+	PNGUp,
+	PNGAverage,
+	PNGPaeth,
+};
+
+static inline void pngData(FILE *file, const uint8_t *data, uint32_t len) {
+	uint32_t adler1 = 1, adler2 = 0;
+	for (uint32_t i = 0; i < len; ++i) {
+		adler1 = (adler1 + data[i]) % 65521;
+		adler2 = (adler1 + adler2) % 65521;
+	}
+	uint32_t zlen = 2 + 5 * ((len + 0xFFFE) / 0xFFFF) + len + 4;
+	pngChunk(file, "IDAT", zlen);
+	pngWrite(file, (uint8_t []) { 0x08, 0x1D }, 2);
+	for (; len > 0xFFFF; data += 0xFFFF, len -= 0xFFFF) {
+		pngWrite(file, (uint8_t []) { 0x00, 0xFF, 0xFF, 0x00, 0x00 }, 5);
+		pngWrite(file, data, 0xFFFF);
+	}
+	pngWrite(file, (uint8_t []) { 0x01, len, len >> 8, ~len, ~len >> 8 }, 5);
+	pngWrite(file, data, len);
+	pngInt32(file, adler2 << 16 | adler1);
+	pngInt32(file, ~pngCRC);
+}
+
+static inline void pngTail(FILE *file) {
+	pngChunk(file, "IEND", 0);
+	pngInt32(file, ~pngCRC);
+}
diff --git a/bin/pngo.c b/bin/pngo.c
new file mode 100644
index 00000000..322cb1ba
--- /dev/null
+++ b/bin/pngo.c
@@ -0,0 +1,812 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <zlib.h>
+
+#define PACKED __attribute__((packed))
+#define PAIR(a, b) ((uint16_t)(a) << 8 | (uint16_t)(b))
+
+#define CRC_INIT (crc32(0, Z_NULL, 0))
+
+static bool verbose;
+static const char *path;
+static FILE *file;
+static uint32_t crc;
+
+static void readExpect(void *ptr, size_t size, const char *expect) {
+	fread(ptr, size, 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	if (feof(file)) errx(EX_DATAERR, "%s: missing %s", path, expect);
+	crc = crc32(crc, ptr, size);
+}
+
+static void writeExpect(const void *ptr, size_t size) {
+	fwrite(ptr, size, 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	crc = crc32(crc, ptr, size);
+}
+
+static const uint8_t Signature[8] = "\x89PNG\r\n\x1A\n";
+
+static void readSignature(void) {
+	uint8_t signature[8];
+	readExpect(signature, 8, "signature");
+	if (0 != memcmp(signature, Signature, 8)) {
+		errx(EX_DATAERR, "%s: invalid signature", path);
+	}
+}
+
+static void writeSignature(void) {
+	writeExpect(Signature, sizeof(Signature));
+}
+
+struct PACKED Chunk {
+	uint32_t size;
+	char type[4];
+};
+
+static const char *typeStr(struct Chunk chunk) {
+	static char buf[5];
+	memcpy(buf, chunk.type, 4);
+	return buf;
+}
+
+static struct Chunk readChunk(void) {
+	struct Chunk chunk;
+	readExpect(&chunk, sizeof(chunk), "chunk");
+	chunk.size = ntohl(chunk.size);
+	crc = crc32(CRC_INIT, (Byte *)chunk.type, sizeof(chunk.type));
+	return chunk;
+}
+
+static void writeChunk(struct Chunk chunk) {
+	chunk.size = htonl(chunk.size);
+	writeExpect(&chunk, sizeof(chunk));
+	crc = crc32(CRC_INIT, (Byte *)chunk.type, sizeof(chunk.type));
+}
+
+static void readCrc(void) {
+	uint32_t expected = crc;
+	uint32_t found;
+	readExpect(&found, sizeof(found), "CRC32");
+	found = ntohl(found);
+	if (found != expected) {
+		errx(
+			EX_DATAERR, "%s: expected CRC32 %08X, found %08X",
+			path, expected, found
+		);
+	}
+}
+
+static void writeCrc(void) {
+	uint32_t net = htonl(crc);
+	writeExpect(&net, sizeof(net));
+}
+
+static void skipChunk(struct Chunk chunk) {
+	if (!(chunk.type[0] & 0x20)) {
+		errx(EX_CONFIG, "%s: unsupported critical chunk %s", path, typeStr(chunk));
+	}
+	uint8_t discard[4096];
+	while (chunk.size > sizeof(discard)) {
+		readExpect(discard, sizeof(discard), "chunk data");
+		chunk.size -= sizeof(discard);
+	}
+	if (chunk.size) readExpect(discard, chunk.size, "chunk data");
+	readCrc();
+}
+
+static struct PACKED {
+	uint32_t width;
+	uint32_t height;
+	uint8_t depth;
+	enum PACKED {
+		Grayscale      = 0,
+		Truecolor      = 2,
+		Indexed        = 3,
+		GrayscaleAlpha = 4,
+		TruecolorAlpha = 6,
+	} color;
+	enum PACKED { Deflate } compression;
+	enum PACKED { Adaptive } filter;
+	enum PACKED { Progressive, Adam7 } interlace;
+} header;
+_Static_assert(13 == sizeof(header), "header size");
+
+static size_t pixelBits(void) {
+	switch (header.color) {
+		case Grayscale:      return 1 * header.depth;
+		case Truecolor:      return 3 * header.depth;
+		case Indexed:        return 1 * header.depth;
+		case GrayscaleAlpha: return 2 * header.depth;
+		case TruecolorAlpha: return 4 * header.depth;
+		default: abort();
+	}
+}
+
+static size_t pixelSize(void) {
+	return (pixelBits() + 7) / 8;
+}
+
+static size_t lineSize(void) {
+	return (header.width * pixelBits() + 7) / 8;
+}
+
+static size_t dataSize(void) {
+	return (1 + lineSize()) * header.height;
+}
+
+static const char *ColorStr[] = {
+	[Grayscale] = "grayscale",
+	[Truecolor] = "truecolor",
+	[Indexed] = "indexed",
+	[GrayscaleAlpha] = "grayscale alpha",
+	[TruecolorAlpha] = "truecolor alpha",
+};
+static void printHeader(void) {
+	fprintf(
+		stderr,
+		"%s: %ux%u %hhu-bit %s\n",
+		path,
+		header.width, header.height,
+		header.depth, ColorStr[header.color]
+	);
+}
+
+static void readHeader(struct Chunk chunk) {
+	if (chunk.size != sizeof(header)) {
+		errx(
+			EX_DATAERR, "%s: expected IHDR size %zu, found %u",
+			path, sizeof(header), chunk.size
+		);
+	}
+	readExpect(&header, sizeof(header), "header");
+	readCrc();
+
+	header.width = ntohl(header.width);
+	header.height = ntohl(header.height);
+
+	if (!header.width) errx(EX_DATAERR, "%s: invalid width 0", path);
+	if (!header.height) errx(EX_DATAERR, "%s: invalid height 0", path);
+	switch (PAIR(header.color, header.depth)) {
+		case PAIR(Grayscale, 1):
+		case PAIR(Grayscale, 2):
+		case PAIR(Grayscale, 4):
+		case PAIR(Grayscale, 8):
+		case PAIR(Grayscale, 16):
+		case PAIR(Truecolor, 8):
+		case PAIR(Truecolor, 16):
+		case PAIR(Indexed, 1):
+		case PAIR(Indexed, 2):
+		case PAIR(Indexed, 4):
+		case PAIR(Indexed, 8):
+		case PAIR(GrayscaleAlpha, 8):
+		case PAIR(GrayscaleAlpha, 16):
+		case PAIR(TruecolorAlpha, 8):
+		case PAIR(TruecolorAlpha, 16):
+			break;
+		default:
+			errx(
+				EX_DATAERR, "%s: invalid color type %hhu and bit depth %hhu",
+				path, header.color, header.depth
+			);
+	}
+	if (header.compression != Deflate) {
+		errx(
+			EX_DATAERR, "%s: invalid compression method %hhu",
+			path, header.compression
+		);
+	}
+	if (header.filter != Adaptive) {
+		errx(EX_DATAERR, "%s: invalid filter method %hhu", path, header.filter);
+	}
+	if (header.interlace > Adam7) {
+		errx(EX_DATAERR, "%s: invalid interlace method %hhu", path, header.interlace);
+	}
+
+	if (verbose) printHeader();
+}
+
+static void writeHeader(void) {
+	if (verbose) printHeader();
+
+	struct Chunk ihdr = { .size = sizeof(header), .type = "IHDR" };
+	writeChunk(ihdr);
+	header.width = htonl(header.width);
+	header.height = htonl(header.height);
+	writeExpect(&header, sizeof(header));
+	writeCrc();
+
+	header.width = ntohl(header.width);
+	header.height = ntohl(header.height);
+}
+
+static struct {
+	uint32_t len;
+	uint8_t entries[256][3];
+} palette;
+
+static struct {
+	uint32_t len;
+	uint8_t alpha[256];
+} trans;
+
+static void paletteClear(void) {
+	palette.len = 0;
+	trans.len = 0;
+}
+
+static uint32_t paletteIndex(bool alpha, const uint8_t *rgba) {
+	uint32_t i;
+	for (i = 0; i < palette.len; ++i) {
+		if (alpha && i < trans.len && trans.alpha[i] != rgba[3]) continue;
+		if (0 == memcmp(palette.entries[i], rgba, 3)) break;
+	}
+	return i;
+}
+
+static bool paletteAdd(bool alpha, const uint8_t *rgba) {
+	uint32_t i = paletteIndex(alpha, rgba);
+	if (i < palette.len) return true;
+	if (i == 256) return false;
+	memcpy(palette.entries[i], rgba, 3);
+	palette.len++;
+	if (alpha) {
+		trans.alpha[i] = rgba[3];
+		trans.len++;
+	}
+	return true;
+}
+
+static void transCompact(void) {
+	uint32_t i;
+	for (i = 0; i < trans.len; ++i) {
+		if (trans.alpha[i] == 0xFF) break;
+	}
+	if (i == trans.len) return;
+
+	for (uint32_t j = i + 1; j < trans.len; ++j) {
+		if (trans.alpha[j] == 0xFF) continue;
+
+		uint8_t alpha = trans.alpha[i];
+		trans.alpha[i] = trans.alpha[j];
+		trans.alpha[j] = alpha;
+
+		uint8_t rgb[3];
+		memcpy(rgb, palette.entries[i], 3);
+		memcpy(palette.entries[i], palette.entries[j], 3);
+		memcpy(palette.entries[j], rgb, 3);
+
+		i++;
+	}
+	trans.len = i;
+}
+
+static void readPalette(struct Chunk chunk) {
+	if (chunk.size % 3) {
+		errx(EX_DATAERR, "%s: PLTE size %u not divisible by 3", path, chunk.size);
+	}
+
+	palette.len = chunk.size / 3;
+	if (palette.len > 256) {
+		errx(EX_DATAERR, "%s: PLTE length %u > 256", path, palette.len);
+	}
+
+	readExpect(palette.entries, chunk.size, "palette data");
+	readCrc();
+
+	if (verbose) fprintf(stderr, "%s: palette length %u\n", path, palette.len);
+}
+
+static void writePalette(void) {
+	if (verbose) fprintf(stderr, "%s: palette length %u\n", path, palette.len);
+	struct Chunk plte = { .size = 3 * palette.len, .type = "PLTE" };
+	writeChunk(plte);
+	writeExpect(palette.entries, plte.size);
+	writeCrc();
+}
+
+static void readTrans(struct Chunk chunk) {
+	trans.len = chunk.size;
+	if (trans.len > 256) {
+		errx(EX_DATAERR, "%s: tRNS length %u > 256", path, trans.len);
+	}
+	readExpect(trans.alpha, chunk.size, "transparency alpha");
+	readCrc();
+	if (verbose) fprintf(stderr, "%s: transparency length %u\n", path, trans.len);
+}
+
+static void writeTrans(void) {
+	if (verbose) fprintf(stderr, "%s: transparency length %u\n", path, trans.len);
+	struct Chunk trns = { .size = trans.len, .type = "tRNS" };
+	writeChunk(trns);
+	writeExpect(trans.alpha, trns.size);
+	writeCrc();
+}
+
+static uint8_t *data;
+
+static void allocData(void) {
+	data = malloc(dataSize());
+	if (!data) err(EX_OSERR, "malloc(%zu)", dataSize());
+}
+
+static void readData(struct Chunk chunk) {
+	if (verbose) fprintf(stderr, "%s: data size %zu\n", path, dataSize());
+
+	struct z_stream_s stream = { .next_out = data, .avail_out = dataSize() };
+	int error = inflateInit(&stream);
+	if (error != Z_OK) errx(EX_SOFTWARE, "%s: inflateInit: %s", path, stream.msg);
+
+	for (;;) {
+		if (0 != memcmp(chunk.type, "IDAT", 4)) {
+			errx(EX_DATAERR, "%s: missing IDAT chunk", path);
+		}
+
+		uint8_t *idat = malloc(chunk.size);
+		if (!idat) err(EX_OSERR, "malloc");
+
+		readExpect(idat, chunk.size, "image data");
+		readCrc();
+
+		stream.next_in = idat;
+		stream.avail_in = chunk.size;
+		int error = inflate(&stream, Z_SYNC_FLUSH);
+		free(idat);
+
+		if (error == Z_STREAM_END) break;
+		if (error != Z_OK) {
+			errx(EX_DATAERR, "%s: inflate: %s", path, stream.msg);
+		}
+
+		chunk = readChunk();
+	}
+
+	inflateEnd(&stream);
+	if ((size_t)stream.total_out != dataSize()) {
+		errx(
+			EX_DATAERR, "%s: expected data size %zu, found %zu",
+			path, dataSize(), (size_t)stream.total_out
+		);
+	}
+
+	if (verbose) {
+		fprintf(
+			stderr, "%s: deflate size %zu\n", path, (size_t)stream.total_in
+		);
+	}
+}
+
+static void writeData(void) {
+	if (verbose) fprintf(stderr, "%s: data size %zu\n", path, dataSize());
+
+	uLong size = compressBound(dataSize());
+	uint8_t *deflate = malloc(size);
+	if (!deflate) err(EX_OSERR, "malloc");
+
+	int error = compress2(deflate, &size, data, dataSize(), Z_BEST_COMPRESSION);
+	if (error != Z_OK) errx(EX_SOFTWARE, "%s: compress2: %d", path, error);
+
+	struct Chunk idat = { .size = size, .type = "IDAT" };
+	writeChunk(idat);
+	writeExpect(deflate, size);
+	writeCrc();
+
+	free(deflate);
+
+	if (verbose) fprintf(stderr, "%s: deflate size %lu\n", path, size);
+}
+
+static void writeEnd(void) {
+	struct Chunk iend = { .size = 0, .type = "IEND" };
+	writeChunk(iend);
+	writeCrc();
+}
+
+enum PACKED Filter {
+	None,
+	Sub,
+	Up,
+	Average,
+	Paeth,
+	FilterCount,
+};
+
+struct Bytes {
+	uint8_t x;
+	uint8_t a;
+	uint8_t b;
+	uint8_t c;
+};
+
+static uint8_t paethPredictor(struct Bytes f) {
+	int32_t p = (int32_t)f.a + (int32_t)f.b - (int32_t)f.c;
+	int32_t pa = abs(p - (int32_t)f.a);
+	int32_t pb = abs(p - (int32_t)f.b);
+	int32_t pc = abs(p - (int32_t)f.c);
+	if (pa <= pb && pa <= pc) return f.a;
+	if (pb <= pc) return f.b;
+	return f.c;
+}
+
+static uint8_t recon(enum Filter type, struct Bytes f) {
+	switch (type) {
+		case None:    return f.x;
+		case Sub:     return f.x + f.a;
+		case Up:      return f.x + f.b;
+		case Average: return f.x + ((uint32_t)f.a + (uint32_t)f.b) / 2;
+		case Paeth:   return f.x + paethPredictor(f);
+		default:      abort();
+	}
+}
+
+static uint8_t filt(enum Filter type, struct Bytes f) {
+	switch (type) {
+		case None:    return f.x;
+		case Sub:     return f.x - f.a;
+		case Up:      return f.x - f.b;
+		case Average: return f.x - ((uint32_t)f.a + (uint32_t)f.b) / 2;
+		case Paeth:   return f.x - paethPredictor(f);
+		default:      abort();
+	}
+}
+
+static struct Line {
+	enum Filter type;
+	uint8_t data[];
+} **lines;
+
+static void allocLines(void) {
+	lines = calloc(header.height, sizeof(*lines));
+	if (!lines) err(EX_OSERR, "calloc(%u, %zu)", header.height, sizeof(*lines));
+}
+
+static void scanlines(void) {
+	size_t stride = 1 + lineSize();
+	for (uint32_t y = 0; y < header.height; ++y) {
+		lines[y] = (struct Line *)&data[y * stride];
+		if (lines[y]->type >= FilterCount) {
+			errx(EX_DATAERR, "%s: invalid filter type %hhu", path, lines[y]->type);
+		}
+	}
+}
+
+static struct Bytes origBytes(uint32_t y, size_t i) {
+	bool a = (i >= pixelSize()), b = (y > 0), c = (a && b);
+	return (struct Bytes) {
+		.x = lines[y]->data[i],
+		.a = a ? lines[y]->data[i - pixelSize()] : 0,
+		.b = b ? lines[y - 1]->data[i] : 0,
+		.c = c ? lines[y - 1]->data[i - pixelSize()] : 0,
+	};
+}
+
+static void reconData(void) {
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (size_t i = 0; i < lineSize(); ++i) {
+			lines[y]->data[i] =
+				recon(lines[y]->type, origBytes(y, i));
+		}
+		lines[y]->type = None;
+	}
+}
+
+static void filterData(void) {
+	if (header.color == Indexed || header.depth < 8) return;
+	for (uint32_t y = header.height - 1; y < header.height; --y) {
+		uint8_t filter[FilterCount][lineSize()];
+		uint32_t heuristic[FilterCount] = {0};
+		enum Filter minType = None;
+		for (enum Filter type = None; type < FilterCount; ++type) {
+			for (size_t i = 0; i < lineSize(); ++i) {
+				filter[type][i] = filt(type, origBytes(y, i));
+				heuristic[type] += abs((int8_t)filter[type][i]);
+			}
+			if (heuristic[type] < heuristic[minType]) minType = type;
+		}
+		lines[y]->type = minType;
+		memcpy(lines[y]->data, filter[minType], lineSize());
+	}
+}
+
+static void discardAlpha(void) {
+	if (header.color != GrayscaleAlpha && header.color != TruecolorAlpha) return;
+	size_t sampleSize = header.depth / 8;
+	size_t colorSize = pixelSize() - sampleSize;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (uint32_t x = 0; x < header.width; ++x) {
+			for (size_t i = 0; i < sampleSize; ++i) {
+				if (lines[y]->data[x * pixelSize() + colorSize + i] != 0xFF) return;
+			}
+		}
+	}
+
+	uint8_t *ptr = data;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		*ptr++ = lines[y]->type;
+		for (uint32_t x = 0; x < header.width; ++x) {
+			memmove(ptr, &lines[y]->data[x * pixelSize()], colorSize);
+			ptr += colorSize;
+		}
+	}
+	header.color = (header.color == GrayscaleAlpha) ? Grayscale : Truecolor;
+	scanlines();
+}
+
+static void discardColor(void) {
+	if (header.color != Truecolor && header.color != TruecolorAlpha) return;
+	size_t sampleSize = header.depth / 8;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (uint32_t x = 0; x < header.width; ++x) {
+			uint8_t *r = &lines[y]->data[x * pixelSize()];
+			uint8_t *g = r + sampleSize;
+			uint8_t *b = g + sampleSize;
+			if (0 != memcmp(r, g, sampleSize)) return;
+			if (0 != memcmp(g, b, sampleSize)) return;
+		}
+	}
+
+	uint8_t *ptr = data;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		*ptr++ = lines[y]->type;
+		for (uint32_t x = 0; x < header.width; ++x) {
+			uint8_t *pixel = &lines[y]->data[x * pixelSize()];
+			memmove(ptr, pixel, sampleSize);
+			ptr += sampleSize;
+			if (header.color == TruecolorAlpha) {
+				memmove(ptr, pixel + 3 * sampleSize, sampleSize);
+				ptr += sampleSize;
+			}
+		}
+	}
+	header.color = (header.color == Truecolor) ? Grayscale : GrayscaleAlpha;
+	scanlines();
+}
+
+static void indexColor(void) {
+	if (header.color != Truecolor && header.color != TruecolorAlpha) return;
+	if (header.depth != 8) return;
+	bool alpha = (header.color == TruecolorAlpha);
+	for (uint32_t y = 0; y < header.height; ++y) {
+		for (uint32_t x = 0; x < header.width; ++x) {
+			if (!paletteAdd(alpha, &lines[y]->data[x * pixelSize()])) return;
+		}
+	}
+	transCompact();
+
+	uint8_t *ptr = data;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		*ptr++ = lines[y]->type;
+		for (uint32_t x = 0; x < header.width; ++x) {
+			*ptr++ = paletteIndex(alpha, &lines[y]->data[x * pixelSize()]);
+		}
+	}
+	header.color = Indexed;
+	scanlines();
+}
+
+static void reduceDepth8(void) {
+	if (header.color != Grayscale && header.color != Indexed) return;
+	if (header.depth != 8) return;
+	if (header.color == Grayscale) {
+		for (uint32_t y = 0; y < header.height; ++y) {
+			for (size_t i = 0; i < lineSize(); ++i) {
+				uint8_t a = lines[y]->data[i];
+				if ((a >> 4) != (a & 0x0F)) return;
+			}
+		}
+	} else if (palette.len > 16) {
+		return;
+	}
+
+	uint8_t *ptr = data;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		*ptr++ = lines[y]->type;
+		for (size_t i = 0; i < lineSize(); i += 2) {
+			uint8_t iByte = lines[y]->data[i];
+			uint8_t jByte = (i + 1 < lineSize()) ? lines[y]->data[i + 1] : 0;
+			uint8_t a = iByte & 0x0F;
+			uint8_t b = jByte & 0x0F;
+			*ptr++ = a << 4 | b;
+		}
+	}
+	header.depth = 4;
+	scanlines();
+}
+
+static void reduceDepth4(void) {
+	if (header.depth != 4) return;
+	if (header.color == Grayscale) {
+		for (uint32_t y = 0; y < header.height; ++y) {
+			for (size_t i = 0; i < lineSize(); ++i) {
+				uint8_t a = lines[y]->data[i] >> 4;
+				uint8_t b = lines[y]->data[i] & 0x0F;
+				if ((a >> 2) != (a & 0x03)) return;
+				if ((b >> 2) != (b & 0x03)) return;
+			}
+		}
+	} else if (palette.len > 4) {
+		return;
+	}
+
+	uint8_t *ptr = data;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		*ptr++ = lines[y]->type;
+		for (size_t i = 0; i < lineSize(); i += 2) {
+			uint8_t iByte = lines[y]->data[i];
+			uint8_t jByte = (i + 1 < lineSize()) ? lines[y]->data[i + 1] : 0;
+			uint8_t a = iByte >> 4 & 0x03, b = iByte & 0x03;
+			uint8_t c = jByte >> 4 & 0x03, d = jByte & 0x03;
+			*ptr++ = a << 6 | b << 4 | c << 2 | d;
+		}
+	}
+	header.depth = 2;
+	scanlines();
+}
+
+static void reduceDepth2(void) {
+	if (header.depth != 2) return;
+	if (header.color == Grayscale) {
+		for (uint32_t y = 0; y < header.height; ++y) {
+			for (size_t i = 0; i < lineSize(); ++i) {
+				uint8_t a = lines[y]->data[i] >> 6;
+				uint8_t b = lines[y]->data[i] >> 4 & 0x03;
+				uint8_t c = lines[y]->data[i] >> 2 & 0x03;
+				uint8_t d = lines[y]->data[i] & 0x03;
+				if ((a >> 1) != (a & 0x01)) return;
+				if ((b >> 1) != (b & 0x01)) return;
+				if ((c >> 1) != (c & 0x01)) return;
+				if ((d >> 1) != (d & 0x01)) return;
+			}
+		}
+	} else if (palette.len > 2) {
+		return;
+	}
+
+	uint8_t *ptr = data;
+	for (uint32_t y = 0; y < header.height; ++y) {
+		*ptr++ = lines[y]->type;
+		for (size_t i = 0; i < lineSize(); i += 2) {
+			uint8_t iByte = lines[y]->data[i];
+			uint8_t jByte = (i + 1 < lineSize()) ? lines[y]->data[i + 1] : 0;
+			uint8_t a = iByte >> 6 & 0x01, b = iByte >> 4 & 0x01;
+			uint8_t c = iByte >> 2 & 0x01, d = iByte & 0x01;
+			uint8_t e = jByte >> 6 & 0x01, f = jByte >> 4 & 0x01;
+			uint8_t g = jByte >> 2 & 0x01, h = jByte & 0x01;
+			*ptr++ = a << 7 | b << 6 | c << 5 | d << 4 | e << 3 | f << 2 | g << 1 | h;
+		}
+	}
+	header.depth = 1;
+	scanlines();
+}
+
+static void reduceDepth(void) {
+	reduceDepth8();
+	reduceDepth4();
+	reduceDepth2();
+}
+
+static void optimize(const char *inPath, const char *outPath) {
+	if (inPath) {
+		path = inPath;
+		file = fopen(path, "r");
+		if (!file) err(EX_NOINPUT, "%s", path);
+	} else {
+		path = "(stdin)";
+		file = stdin;
+	}
+
+	readSignature();
+	struct Chunk ihdr = readChunk();
+	if (0 != memcmp(ihdr.type, "IHDR", 4)) {
+		errx(EX_DATAERR, "%s: expected IHDR, found %s", path, typeStr(ihdr));
+	}
+	readHeader(ihdr);
+	if (header.interlace != Progressive) {
+		errx(
+			EX_CONFIG, "%s: unsupported interlace method %hhu",
+			path, header.interlace
+		);
+	}
+
+	paletteClear();
+	allocData();
+	for (;;) {
+		struct Chunk chunk = readChunk();
+		if (0 == memcmp(chunk.type, "PLTE", 4)) {
+			readPalette(chunk);
+		} else if (0 == memcmp(chunk.type, "tRNS", 4)) {
+			readTrans(chunk);
+		} else if (0 == memcmp(chunk.type, "IDAT", 4)) {
+			readData(chunk);
+		} else if (0 != memcmp(chunk.type, "IEND", 4)) {
+			skipChunk(chunk);
+		} else {
+			break;
+		}
+	}
+
+	fclose(file);
+
+	allocLines();
+	scanlines();
+	reconData();
+
+	discardAlpha();
+	discardColor();
+	indexColor();
+	reduceDepth();
+	filterData();
+	free(lines);
+
+	if (outPath) {
+		path = outPath;
+		file = fopen(path, "w");
+		if (!file) err(EX_CANTCREAT, "%s", path);
+	} else {
+		path = "(stdout)";
+		file = stdout;
+	}
+
+	writeSignature();
+	writeHeader();
+	if (header.color == Indexed) {
+		writePalette();
+		if (trans.len) writeTrans();
+	}
+	writeData();
+	writeEnd();
+	free(data);
+
+	int error = fclose(file);
+	if (error) err(EX_IOERR, "%s", path);
+}
+
+int main(int argc, char *argv[]) {
+	bool stdio = false;
+	char *output = NULL;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "co:v"))) {
+		switch (opt) {
+			break; case 'c': stdio = true;
+			break; case 'o': output = optarg;
+			break; case 'v': verbose = true;
+			break; default: return EX_USAGE;
+		}
+	}
+
+	if (argc - optind == 1 && (output || stdio)) {
+		optimize(argv[optind], output);
+	} else if (optind < argc) {
+		for (int i = optind; i < argc; ++i) {
+			optimize(argv[i], argv[i]);
+		}
+	} else {
+		optimize(NULL, output);
+	}
+
+	return EX_OK;
+}
diff --git a/bin/psf2png.c b/bin/psf2png.c
new file mode 100644
index 00000000..1aaa8635
--- /dev/null
+++ b/bin/psf2png.c
@@ -0,0 +1,107 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+#include "png.h"
+
+int main(int argc, char *argv[]) {
+	uint32_t cols = 32;
+	const char *str = NULL;
+	uint32_t fg = 0xFFFFFF;
+	uint32_t bg = 0x000000;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "b:c:f:s:"))) {
+		switch (opt) {
+			break; case 'b': bg = strtoul(optarg, NULL, 16);
+			break; case 'c': cols = strtoul(optarg, NULL, 0);
+			break; case 'f': fg = strtoul(optarg, NULL, 16);
+			break; case 's': str = optarg;
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (!cols && str) cols = strlen(str);
+	if (!cols) return EX_USAGE;
+
+	const char *path = NULL;
+	if (optind < argc) path = argv[optind];
+	
+	FILE *file = path ? fopen(path, "r") : stdin;
+	if (!file) err(EX_NOINPUT, "%s", path);
+	if (!path) path = "(stdin)";
+
+	struct {
+		uint32_t magic;
+		uint32_t version;
+		uint32_t size;
+		uint32_t flags;
+		struct {
+			uint32_t len;
+			uint32_t size;
+			uint32_t height;
+			uint32_t width;
+		} glyph;
+	} header;
+	size_t len = fread(&header, sizeof(header), 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	if (len < 1) errx(EX_DATAERR, "%s: truncated header", path);
+
+	uint32_t widthBytes = (header.glyph.width + 7) / 8;
+	uint8_t glyphs[header.glyph.len][header.glyph.height][widthBytes];
+	len = fread(glyphs, header.glyph.size, header.glyph.len, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	if (len < header.glyph.len) {
+		errx(EX_DATAERR, "%s: truncated glyphs", path);
+	}
+	fclose(file);
+
+	uint32_t count = (str ? strlen(str) : header.glyph.len);
+	uint32_t width = header.glyph.width * cols;
+	uint32_t rows = (count + cols - 1) / cols;
+	uint32_t height = header.glyph.height * rows;
+
+	pngHead(stdout, width, height, 8, PNGIndexed);
+	uint8_t pal[] = {
+		bg >> 16, bg >> 8, bg,
+		fg >> 16, fg >> 8, fg,
+	};
+	pngPalette(stdout, pal, sizeof(pal));
+
+	uint8_t data[height][1 + width];
+	memset(data, PNGNone, sizeof(data));
+
+	for (uint32_t i = 0; i < count; ++i) {
+		uint32_t row = header.glyph.height * (i / cols);
+		uint32_t col = 1 + header.glyph.width * (i % cols);
+		uint32_t g = (str ? str[i] : i);
+		for (uint32_t y = 0; y < header.glyph.height; ++y) {
+			for (uint32_t x = 0; x < header.glyph.width; ++x) {
+				uint8_t bit = glyphs[g][y][x / 8] >> (7 - x % 8) & 1;
+				data[row + y][col + x] = bit;
+			}
+		}
+	}
+
+	pngData(stdout, (uint8_t *)data, sizeof(data));
+	pngTail(stdout);
+}
diff --git a/bin/psfed.c b/bin/psfed.c
new file mode 100644
index 00000000..4f46b500
--- /dev/null
+++ b/bin/psfed.c
@@ -0,0 +1,577 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <locale.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+#include <wchar.h>
+
+static const wchar_t CP437[256] =
+	L"\0☺☻♥♦♣♠•◘○◙♂♀♪♫☼"
+	L"►◄↕‼¶§▬↨↑↓→←∟↔▲▼"
+	L" !\"#$%&'()*+,-./"
+	L"0123456789:;<=>?"
+	L"@ABCDEFGHIJKLMNO"
+	L"PQRSTUVWXYZ[\\]^_"
+	L"`abcdefghijklmno"
+	L"pqrstuvwxyz{|}~⌂"
+	L"ÇüéâäàåçêëèïîìÄÅ"
+	L"ÉæÆôöòûùÿÖÜ¢£¥₧ƒ"
+	L"áíóúñѪº¿⌐¬½¼¡«»"
+	L"░▒▓│┤╡╢╖╕╣║╗╝╜╛┐"
+	L"└┴┬├─┼╞╟╚╔╩╦╠═╬╧"
+	L"╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀"
+	L"αßΓπΣσµτΦΘΩδ∞φε∩"
+	L"≡±≥≤⌠⌡÷≈°∙·√ⁿ²■\0";
+
+static struct {
+	uint32_t width;
+	uint32_t height;
+	uint32_t *buffer;
+	uint32_t background;
+} frame;
+
+static void frameClear(void) {
+	for (uint32_t i = 0; i < frame.width * frame.height; ++i) {
+		frame.buffer[i] = frame.background;
+	}
+}
+
+static void frameOpen(void) {
+	const char *dev = getenv("FRAMEBUFFER");
+	if (!dev) dev = "/dev/fb0";
+
+	int fd = open(dev, O_RDWR);
+	if (fd < 0) err(EX_OSFILE, "%s", dev);
+
+	struct fb_var_screeninfo info;
+	int error = ioctl(fd, FBIOGET_VSCREENINFO, &info);
+	if (error) err(EX_IOERR, "%s", dev);
+
+	frame.width = info.xres;
+	frame.height = 3 * info.yres / 4;
+	frame.buffer = mmap(
+		NULL, sizeof(*frame.buffer) * frame.width * frame.height,
+		PROT_READ | PROT_WRITE, MAP_SHARED,
+		fd, 0
+	);
+	if (frame.buffer == MAP_FAILED) err(EX_IOERR, "%s", dev);
+	close(fd);
+
+	frame.background = frame.buffer[0];
+	atexit(frameClear);
+}
+
+static const uint32_t Magic = 0x864AB572;
+static const uint32_t Version = 0;
+static const uint32_t FlagUnicode = 1 << 0;
+static uint32_t bytes(uint32_t bits) {
+	return (bits + 7) / 8;
+}
+
+static char *path;
+static struct {
+	uint32_t magic;
+	uint32_t version;
+	uint32_t size;
+	uint32_t flags;
+	struct {
+		uint32_t len;
+		uint32_t size;
+		uint32_t height;
+		uint32_t width;
+	} glyph;
+} header;
+static uint8_t *glyphs;
+
+static void fileRead(uint32_t newLen, uint32_t newWidth, uint32_t newHeight) {
+	FILE *file = fopen(path, "r");
+	if (file) {
+		size_t len = fread(&header, sizeof(header), 1, file);
+		if (ferror(file)) err(EX_IOERR, "%s", path);
+		if (len < 1) errx(EX_DATAERR, "%s: truncated header", path);
+
+	} else {
+		if (errno != ENOENT) err(EX_NOINPUT, "%s", path);
+		header.magic = Magic;
+		header.version = Version;
+		header.size = sizeof(header);
+		header.flags = 0;
+		header.glyph.len = newLen;
+		header.glyph.size = bytes(newWidth) * newHeight;
+		header.glyph.height = newHeight;
+		header.glyph.width = newWidth;
+	}
+
+	if (header.magic != Magic) {
+		errx(EX_DATAERR, "%s: invalid magic %08X", path, header.magic);
+	}
+	if (header.version != Version) {
+		errx(EX_DATAERR, "%s: unsupported version %u", path, header.version);
+	}
+	if (header.flags & FlagUnicode) {
+		errx(EX_DATAERR, "%s: unsupported unicode table", path);
+	}
+	if (header.flags) {
+		errx(EX_DATAERR, "%s: unsupported flags %08X", path, header.flags);
+	}
+
+	if (file && header.size > sizeof(header)) {
+		int error = fseek(file, header.size, SEEK_SET);
+		if (error) err(EX_IOERR, "%s", path);
+
+		warnx("%s: truncating long header", path);
+		header.size = sizeof(header);
+	}
+
+	glyphs = calloc(header.glyph.len, header.glyph.size);
+	if (!glyphs) err(EX_OSERR, "calloc");
+
+	if (file) {
+		size_t len = fread(glyphs, header.glyph.size, header.glyph.len, file);
+		if (ferror(file)) err(EX_IOERR, "%s", path);
+		if (len < header.glyph.len) {
+			errx(EX_DATAERR, "%s: truncated glyphs", path);
+		}
+		fclose(file);
+	}
+}
+
+static void fileWrite(void) {
+	FILE *file = fopen(path, "w");
+	if (!file) err(EX_CANTCREAT, "%s", path);
+
+	fwrite(&header, sizeof(header), 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+
+	fwrite(glyphs, header.glyph.size, header.glyph.len, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+
+	int error = fclose(file);
+	if (error) err(EX_IOERR, "%s", path);
+}
+
+static uint8_t *glyph(uint32_t index) {
+	return &glyphs[header.glyph.size * index];
+}
+static uint8_t *bitByte(uint32_t index, uint32_t x, uint32_t y) {
+	return &glyph(index)[bytes(header.glyph.width) * y + x / 8];
+}
+static uint8_t bitGet(uint32_t index, uint32_t x, uint32_t y) {
+	return *bitByte(index, x, y) >> (7 - x % 8) & 1;
+}
+static void bitFlip(uint32_t index, uint32_t x, uint32_t y) {
+	*bitByte(index, x, y) ^= 1 << (7 - x % 8);
+}
+static void bitSet(uint32_t index, uint32_t x, uint32_t y, uint8_t bit) {
+	*bitByte(index, x, y) &= ~(1 << (7 - x % 8));
+	*bitByte(index, x, y) |= bit << (7 - x % 8);
+}
+
+static void drawGlyph(
+	uint32_t destX, uint32_t destY, uint32_t scale, uint32_t index,
+	uint32_t selectX, uint32_t selectY, uint32_t guideX, uint32_t guideY
+) {
+	destX <<= scale;
+	destY <<= scale;
+
+	for (uint32_t y = 0; y < (header.glyph.height << scale); ++y) {
+		if (destY + y >= frame.height) break;
+		for (uint32_t x = 0; x < (header.glyph.width << scale); ++x) {
+			if (destX + x >= frame.width) break;
+
+			uint32_t glyphX = x >> scale;
+			uint32_t glyphY = y >> scale;
+			uint32_t fill = -bitGet(index, glyphX, glyphY);
+			if (selectX & 1 << glyphX && selectY & 1 << glyphY) fill ^= 0x77;
+			if (guideX & 1 << glyphX || guideY & 1 << glyphY) fill ^= 0x3300;
+
+			frame.buffer[frame.width * (destY + y) + destX + x] = fill;
+		}
+	}
+}
+
+static void drawBorder(uint32_t destX, uint32_t destY, uint32_t scale) {
+	destX <<= scale;
+	destY <<= scale;
+
+	for (uint32_t y = 0; y < destY; ++y) {
+		if (y >= frame.height) break;
+		uint32_t fill = -(y >> scale & 1) ^ 0x555555;
+		for (uint32_t x = 0; x < (uint32_t)(1 << scale); ++x) {
+			if (destX + x >= frame.width) break;
+			frame.buffer[frame.width * y + destX + x] = fill;
+		}
+	}
+
+	for (uint32_t x = 0; x < destX; ++x) {
+		if (x >= frame.width) break;
+		uint32_t fill = -(x >> scale & 1) ^ 0x555555;
+		for (uint32_t y = 0; y < (uint32_t)(1 << scale); ++y) {
+			if (destY + y >= frame.height) break;
+			frame.buffer[frame.width * (destY + y) + x] = fill;
+		}
+	}
+}
+
+enum { LF = '\n', Esc = '\33', Del = '\177' };
+
+static enum {
+	Normal,
+	Edit,
+	Preview,
+	Discard,
+} mode;
+
+static struct {
+	uint32_t scale;
+	uint32_t index;
+	bool modified;
+	bool to;
+	uint32_t from;
+} normal;
+
+static struct {
+	uint32_t scale;
+	uint32_t index;
+	uint32_t x;
+	uint32_t y;
+	uint32_t guideX;
+	uint32_t guideY;
+	uint8_t *undo;
+	uint8_t *copy;
+} edit = {
+	.scale = 4,
+};
+
+static const uint32_t NormalCols = 32;
+static void drawNormal(void) {
+	for (uint32_t i = 0; i < header.glyph.len; ++i) {
+		drawGlyph(
+			header.glyph.width * (i % NormalCols),
+			header.glyph.height * (i  / NormalCols),
+			normal.scale, i,
+			-(i == normal.index), -(i == normal.index), 0, 0
+		);
+	}
+}
+
+static void normalDec(uint32_t n) {
+	if (normal.index >= n) normal.index -= n;
+}
+static void normalInc(uint32_t n) {
+	if (normal.index + n < header.glyph.len) normal.index += n;
+}
+static void normalPrint(const char *prefix) {
+	if (normal.index <= 256) {
+		printf(
+			"%s: %02X '%lc'\n",
+			prefix, normal.index, (wint_t)CP437[normal.index]
+		);
+	} else {
+		printf("%s: %02X\n", prefix, normal.index);
+	}
+}
+
+static void inputNormal(char ch) {
+	if (normal.to) {
+		if (ch < header.glyph.len) normal.index = ch;
+		normalPrint("index");
+		normal.to = false;
+		return;
+	}
+
+	switch (ch) {
+		break; case 'q': {
+			if (!normal.modified) exit(EX_OK);
+			mode = Discard;
+		}
+		break; case 'w': {
+			fileWrite();
+			printf("write: %s\n", path);
+			normal.modified = false;
+		}
+		break; case '-': if (normal.scale) normal.scale--; frameClear();
+		break; case '+': normal.scale++;
+		break; case 'h': normalDec(1); normalPrint("index");
+		break; case 'l': normalInc(1); normalPrint("index");
+		break; case 'k': normalDec(NormalCols); normalPrint("index");
+		break; case 'j': normalInc(NormalCols); normalPrint("index");
+		break; case 'f': normal.from = normal.index; normal.to = true;
+		break; case 047: normal.index = normal.from; normalPrint("index");
+		break; case 'y': {
+			if (!edit.copy) edit.copy = malloc(header.glyph.size);
+			if (!edit.copy) err(EX_OSERR, "malloc");
+			memcpy(edit.copy, glyph(normal.index), header.glyph.size);
+			normalPrint("copy");
+		}
+		break; case 'e': {
+			normal.modified = true;
+			edit.index = normal.index;
+			if (!edit.undo) edit.undo = malloc(header.glyph.size);
+			if (!edit.undo) err(EX_OSERR, "malloc");
+			memcpy(edit.undo, glyph(edit.index), header.glyph.size);
+			mode = Edit;
+			frameClear();
+		}
+		break; case 'i': mode = Preview; frameClear();
+	}
+}
+
+static void drawEdit(void) {
+	drawGlyph(
+		0, 0, edit.scale, edit.index,
+		1 << edit.x, 1 << edit.y, edit.guideX, edit.guideY
+	);
+	drawBorder(header.glyph.width, header.glyph.height, edit.scale);
+	drawGlyph(
+		header.glyph.width << edit.scale,
+		header.glyph.height << edit.scale,
+		0, edit.index,
+		0, 0, 0, 0
+	);
+}
+
+static void inputEdit(char ch) {
+	switch (ch) {
+		break; case Esc: mode = Normal; frameClear();
+
+		break; case '-': if (edit.scale) edit.scale--; frameClear();
+		break; case '+': edit.scale++;
+		break; case 'g': edit.guideY ^= 1 << edit.y;
+		break; case 'G': edit.guideX ^= 1 << edit.x;
+
+		break; case 'h': if (edit.x) edit.x--;
+		break; case 'l': if (edit.x + 1 < header.glyph.width) edit.x++;
+		break; case 'k': if (edit.y) edit.y--;
+		break; case 'j': if (edit.y + 1 < header.glyph.height) edit.y++;
+		break; case ' ': bitFlip(edit.index, edit.x, edit.y);
+
+		break; case 'r': {
+			for (uint32_t y = 0; y < header.glyph.height; ++y) {
+				for (uint32_t x = 0; x < header.glyph.width; ++x) {
+					bitFlip(edit.index, x, y);
+				}
+			}
+		}
+
+		break; case 'H': {
+			for (uint32_t x = 0; x < header.glyph.width; ++x) {
+				for (uint32_t y = 0; y < header.glyph.height; ++y) {
+					if (x + 1 < header.glyph.width) {
+						bitSet(edit.index, x, y, bitGet(edit.index, x + 1, y));
+					} else {
+						bitSet(edit.index, x, y, 0);
+					}
+				}
+			}
+		}
+
+		break; case 'L': {
+			uint32_t width = header.glyph.width;
+			for (uint32_t x = width - 1; x < width; --x) {
+				for (uint32_t y = 0; y < header.glyph.height; ++y) {
+					if (x - 1 < width) {
+						bitSet(edit.index, x, y, bitGet(edit.index, x - 1, y));
+					} else {
+						bitSet(edit.index, x, y, 0);
+					}
+				}
+			}
+		}
+
+		break; case 'K': {
+			for (uint32_t y = 0; y < header.glyph.height; ++y) {
+				for (uint32_t x = 0; x < header.glyph.width; ++x) {
+					if (y + 1 < header.glyph.height) {
+						bitSet(edit.index, x, y, bitGet(edit.index, x, y + 1));
+					} else {
+						bitSet(edit.index, x, y, 0);
+					}
+				}
+			}
+		}
+
+		break; case 'J': {
+			uint32_t height = header.glyph.height;
+			for (uint32_t y = height - 1; y < height; --y) {
+				for (uint32_t x = 0; x < header.glyph.width; ++x) {
+					if (y - 1 < height) {
+						bitSet(edit.index, x, y, bitGet(edit.index, x, y - 1));
+					} else {
+						bitSet(edit.index, x, y, 0);
+					}
+				}
+			}
+		}
+
+		break; case 'p': {
+			if (!edit.copy) break;
+			memcpy(glyph(edit.index), edit.copy, header.glyph.size);
+		}
+		break; case 'u': {
+			if (!edit.undo) break;
+			memcpy(glyph(edit.index), edit.undo, header.glyph.size);
+		}
+	}
+}
+
+enum { PreviewRows = 8, PreviewCols = 64 };
+static struct {
+	uint32_t glyphs[PreviewRows * PreviewCols];
+	uint32_t index;
+} preview;
+
+static void drawPreview(void) {
+	for (uint32_t i = 0; i < PreviewRows * PreviewCols; ++i) {
+		drawGlyph(
+			header.glyph.width * (i % PreviewCols),
+			header.glyph.height * (i / PreviewCols),
+			0, preview.glyphs[i],
+			-(i == preview.index), -(i == preview.index), 0, 0
+		);
+	}
+}
+
+static void inputPreview(char ch) {
+	switch (ch) {
+		break; case Esc: mode = Normal; frameClear();
+		break; case Del: {
+			if (preview.index) preview.index--;
+			preview.glyphs[preview.index] = 0;
+		}
+		break; case LF: {
+			uint32_t tail = PreviewCols - (preview.index % PreviewCols);
+			memset(
+				&preview.glyphs[preview.index],
+				0, sizeof(preview.glyphs[0]) * tail
+			);
+			preview.index += tail;
+		}
+		break; default: preview.glyphs[preview.index++] = ch;
+	}
+	preview.index %= PreviewRows * PreviewCols;
+}
+
+static void drawDiscard(void) {
+	printf("discard modifications? ");
+	fflush(stdout);
+}
+
+static void inputDiscard(char ch) {
+	printf("%c\n", ch);
+	if (ch == 'Y' || ch == 'y') exit(EX_OK);
+	mode = Normal;
+}
+
+static void draw(void) {
+	switch (mode) {
+		break; case Normal: drawNormal();
+		break; case Edit: drawEdit();
+		break; case Preview: drawPreview();
+		break; case Discard: drawDiscard();
+	}
+}
+
+static void input(char ch) {
+	switch (mode) {
+		break; case Normal: inputNormal(ch);
+		break; case Edit: inputEdit(ch);
+		break; case Preview: inputPreview(ch);
+		break; case Discard: inputDiscard(ch);
+	}
+}
+
+static struct termios saveTerm;
+static void restoreTerm(void) {
+	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
+}
+
+int main(int argc, char *argv[]) {
+	setlocale(LC_CTYPE, "");
+
+	uint32_t newLen = 256;
+	uint32_t newWidth = 8;
+	uint32_t newHeight = 16;
+	uint32_t setHeight = 0;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "H:g:h:w:"))) {
+		switch (opt) {
+			break; case 'H': setHeight = strtoul(optarg, NULL, 0);
+			break; case 'g': newLen = strtoul(optarg, NULL, 0);
+			break; case 'h': newHeight = strtoul(optarg, NULL, 0);
+			break; case 'w': newWidth = strtoul(optarg, NULL, 0);
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (!newLen || !newWidth || !newHeight) return EX_USAGE;
+	if (optind == argc) return EX_USAGE;
+
+	path = strdup(argv[optind]);
+	fileRead(newLen, newWidth, newHeight);
+
+	if (setHeight) {
+		if (setHeight < header.glyph.height) {
+			errx(EX_CONFIG, "cannot decrease height");
+		}
+
+		uint32_t setSize = bytes(header.glyph.width) * setHeight;
+		uint8_t *setGlyphs = calloc(header.glyph.len, setSize);
+		for (uint32_t i = 0; i < header.glyph.len; ++i) {
+			memcpy(&setGlyphs[setSize * i], glyph(i), header.glyph.size);
+		}
+		free(glyphs);
+		glyphs = setGlyphs;
+
+		header.glyph.height = setHeight;
+		header.glyph.size = setSize;
+		normal.modified = true;
+	}
+
+	frameOpen();
+	frameClear();
+
+	int error = tcgetattr(STDIN_FILENO, &saveTerm);
+	if (error) err(EX_IOERR, "tcgetattr");
+	atexit(restoreTerm);
+
+	struct termios term = saveTerm;
+	term.c_lflag &= ~(ICANON | ECHO);
+	error = tcsetattr(STDIN_FILENO, TCSADRAIN, &term);
+	if (error) err(EX_IOERR, "tcsetattr");
+
+	for (;;) {
+		draw();
+		char ch;
+		ssize_t size = read(STDIN_FILENO, &ch, 1);
+		if (size < 0) err(EX_IOERR, "read");
+		if (!size) return EX_SOFTWARE;
+		input(ch);
+	}
+}
diff --git a/bin/ptee.c b/bin/ptee.c
new file mode 100644
index 00000000..6a9a16b4
--- /dev/null
+++ b/bin/ptee.c
@@ -0,0 +1,116 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+
+#if defined __FreeBSD__
+#include <libutil.h>
+#elif defined __linux__
+#include <pty.h>
+#else
+#include <util.h>
+#endif
+
+typedef unsigned char byte;
+
+static struct termios saveTerm;
+static void restoreTerm(void) {
+	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
+}
+
+int main(int argc, char *argv[]) {
+	if (argc < 2) return EX_USAGE;
+	if (isatty(STDOUT_FILENO)) errx(EX_USAGE, "stdout is not redirected");
+
+	int error = tcgetattr(STDIN_FILENO, &saveTerm);
+	if (error) err(EX_IOERR, "tcgetattr");
+	atexit(restoreTerm);
+
+	struct termios raw = saveTerm;
+	cfmakeraw(&raw);
+	error = tcsetattr(STDIN_FILENO, TCSADRAIN, &raw);
+	if (error) err(EX_IOERR, "tcsetattr");
+
+	struct winsize window;
+	error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window);
+	if (error) err(EX_IOERR, "ioctl");
+
+	int pty;
+	pid_t pid = forkpty(&pty, NULL, NULL, &window);
+	if (pid < 0) err(EX_OSERR, "forkpty");
+
+	if (!pid) {
+		execvp(argv[1], &argv[1]);
+		err(EX_NOINPUT, "%s", argv[1]);
+	}
+
+	bool stop = false;
+
+	byte buf[4096];
+	struct pollfd fds[2] = {
+		{ .events = POLLIN, .fd = STDIN_FILENO },
+		{ .events = POLLIN, .fd = pty },
+	};
+	while (0 < poll(fds, 2, -1)) {
+		if (fds[0].revents & POLLIN) {
+			ssize_t rlen = read(STDIN_FILENO, buf, sizeof(buf));
+			if (rlen < 0) err(EX_IOERR, "read");
+
+			if (rlen == 1 && buf[0] == CTRL('S')) {
+				stop ^= true;
+				continue;
+			}
+
+			if (rlen == 1 && buf[0] == CTRL('Q')) {
+				char dump[] = "\x1B[10i";
+				ssize_t wlen = write(STDOUT_FILENO, dump, sizeof(dump) - 1);
+				if (wlen < 0) err(EX_IOERR, "write");
+				continue;
+			}
+
+			ssize_t wlen = write(pty, buf, rlen);
+			if (wlen < 0) err(EX_IOERR, "write");
+		}
+
+		if (fds[1].revents & POLLIN) {
+			ssize_t rlen = read(pty, buf, sizeof(buf));
+			if (rlen < 0) err(EX_IOERR, "read");
+
+			ssize_t wlen = write(STDIN_FILENO, buf, rlen);
+			if (wlen < 0) err(EX_IOERR, "write");
+
+			if (!stop) {
+				wlen = write(STDOUT_FILENO, buf, rlen);
+				if (wlen < 0) err(EX_IOERR, "write");
+			}
+		}
+
+		int status;
+		pid_t dead = waitpid(pid, &status, WNOHANG);
+		if (dead < 0) err(EX_OSERR, "waitpid");
+		if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
+	}
+	err(EX_IOERR, "poll");
+}
diff --git a/bin/relay.c b/bin/relay.c
new file mode 100644
index 00000000..aa7913c9
--- /dev/null
+++ b/bin/relay.c
@@ -0,0 +1,218 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7:
+ *
+ * If you modify this Program, or any covered work, by linking or
+ * combining it with LibreSSL (or a modified version of that library),
+ * containing parts covered by the terms of the OpenSSL License and the
+ * original SSLeay license, the licensors of this Program grant you
+ * additional permission to convey the resulting work. Corresponding
+ * Source for a non-source form of such a combination shall include the
+ * source code for the parts of LibreSSL used as well as that of the
+ * covered work.
+ */
+
+#include <err.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sysexits.h>
+#include <tls.h>
+#include <unistd.h>
+
+#ifdef __FreeBSD__
+#include <sys/capsicum.h>
+#endif
+
+static void clientWrite(struct tls *client, const char *ptr, size_t len) {
+	while (len) {
+		ssize_t ret = tls_write(client, ptr, len);
+		if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) continue;
+		if (ret < 0) errx(EX_IOERR, "tls_write: %s", tls_error(client));
+		ptr += ret;
+		len -= ret;
+	}
+}
+
+static void clientFormat(struct tls *client, const char *format, ...) {
+	char buf[1024];
+	va_list ap;
+	va_start(ap, format);
+	int len = vsnprintf(buf, sizeof(buf), format, ap);
+	va_end(ap);
+	if ((size_t)len > sizeof(buf) - 1) errx(EX_DATAERR, "message too large");
+	clientWrite(client, buf, len);
+}
+
+static void clientHandle(struct tls *client, const char *chan, char *line) {
+	char *prefix = NULL;
+	if (line[0] == ':') {
+		prefix = strsep(&line, " ") + 1;
+		if (!line) errx(EX_PROTOCOL, "unexpected eol");
+	}
+
+	char *command = strsep(&line, " ");
+	if (!strcmp(command, "001") || !strcmp(command, "INVITE")) {
+		clientFormat(client, "JOIN :%s\r\n", chan);
+	} else if (!strcmp(command, "PING")) {
+		clientFormat(client, "PONG %s\r\n", line);
+	}
+	if (strcmp(command, "PRIVMSG") && strcmp(command, "NOTICE")) return;
+
+	if (!prefix) errx(EX_PROTOCOL, "message without prefix");
+	char *nick = strsep(&prefix, "!");
+
+	if (!line) errx(EX_PROTOCOL, "message without destination");
+	char *dest = strsep(&line, " ");
+	if (strcmp(dest, chan)) return;
+
+	if (!line || line[0] != ':') errx(EX_PROTOCOL, "message without message");
+	line = &line[1];
+
+	if (!strncmp(line, "\1ACTION ", 8)) {
+		line = &line[8];
+		size_t len = strcspn(line, "\1");
+		printf("* %c\u200C%s %.*s\n", nick[0], &nick[1], (int)len, line);
+	} else if (command[0] == 'N') {
+		printf("-%c\u200C%s- %s\n", nick[0], &nick[1], line);
+	} else {
+		printf("<%c\u200C%s> %s\n", nick[0], &nick[1], line);
+	}
+}
+
+#ifdef __FreeBSD__
+static void limit(int fd, const cap_rights_t *rights) {
+	int error = cap_rights_limit(fd, rights);
+	if (error) err(EX_OSERR, "cap_rights_limit");
+}
+#endif
+
+int main(int argc, char *argv[]) {
+	int error;
+
+	if (argc < 5) return EX_USAGE;
+	const char *host = argv[1];
+	const char *port = argv[2];
+	const char *nick = argv[3];
+	const char *chan = argv[4];
+
+	setlinebuf(stdout);
+	signal(SIGPIPE, SIG_IGN);
+
+	struct tls_config *config = tls_config_new();
+	if (!config) errx(EX_SOFTWARE, "tls_config_new");
+
+	error = tls_config_set_ciphers(config, "compat");
+	if (error) {
+		errx(EX_SOFTWARE, "tls_config_set_ciphers: %s", tls_config_error(config));
+	}
+
+	struct tls *client = tls_client();
+	if (!client) errx(EX_SOFTWARE, "tls_client");
+
+	error = tls_configure(client, config);
+	if (error) errx(EX_SOFTWARE, "tls_configure: %s", tls_error(client));
+	tls_config_free(config);
+
+	struct addrinfo *head;
+	struct addrinfo hints = {
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = SOCK_STREAM,
+		.ai_protocol = IPPROTO_TCP,
+	};
+	error = getaddrinfo(host, port, &hints, &head);
+	if (error) errx(EX_NOHOST, "getaddrinfo: %s", gai_strerror(error));
+
+	int sock = -1;
+	for (struct addrinfo *ai = head; ai; ai = ai->ai_next) {
+		sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+		if (sock < 0) err(EX_OSERR, "socket");
+
+		error = connect(sock, ai->ai_addr, ai->ai_addrlen);
+		if (!error) break;
+
+		close(sock);
+		sock = -1;
+	}
+	if (sock < 0) err(EX_UNAVAILABLE, "connect");
+	freeaddrinfo(head);
+
+	error = tls_connect_socket(client, sock, host);
+	if (error) errx(EX_PROTOCOL, "tls_connect: %s", tls_error(client));
+
+#ifdef __FreeBSD__
+	error = cap_enter();
+	if (error) err(EX_OSERR, "cap_enter");
+
+	cap_rights_t rights;
+	cap_rights_init(&rights, CAP_WRITE);
+	limit(STDOUT_FILENO, &rights);
+	limit(STDERR_FILENO, &rights);
+
+	cap_rights_init(&rights, CAP_EVENT, CAP_READ);
+	limit(STDIN_FILENO, &rights);
+
+	cap_rights_set(&rights, CAP_WRITE);
+	limit(sock, &rights);
+#endif
+
+	clientFormat(client, "NICK :%s\r\nUSER %s 0 * :%s\r\n", nick, nick, nick);
+
+	char *input = NULL;
+	size_t cap = 0;
+
+	char buf[4096];
+	size_t len = 0;
+
+	struct pollfd fds[2] = {
+		{ .events = POLLIN, .fd = STDIN_FILENO },
+		{ .events = POLLIN, .fd = sock },
+	};
+	while (0 < poll(fds, 2, -1)) {
+		if (fds[0].revents) {
+			ssize_t len = getline(&input, &cap, stdin);
+			if (len < 0) err(EX_IOERR, "getline");
+			input[len - 1] = '\0';
+			clientFormat(client, "NOTICE %s :%s\r\n", chan, input);
+		}
+		if (!fds[1].revents) continue;
+
+		ssize_t read = tls_read(client, &buf[len], sizeof(buf) - len);
+		if (read == TLS_WANT_POLLIN || read == TLS_WANT_POLLOUT) continue;
+		if (read < 0) errx(EX_IOERR, "tls_read: %s", tls_error(client));
+		if (!read) return EX_UNAVAILABLE;
+		len += read;
+
+		char *crlf;
+		char *line = buf;
+		for (;;) {
+			crlf = memmem(line, &buf[len] - line, "\r\n", 2);
+			if (!crlf) break;
+			crlf[0] = '\0';
+			clientHandle(client, chan, line);
+			line = &crlf[2];
+		}
+		len -= line - buf;
+		memmove(buf, line, len);
+	}
+	err(EX_IOERR, "poll");
+}
diff --git a/bin/scheme.c b/bin/scheme.c
new file mode 100644
index 00000000..ec5a2eec
--- /dev/null
+++ b/bin/scheme.c
@@ -0,0 +1,256 @@
+/* Copyright (C) 2018, 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+#include "png.h"
+
+typedef unsigned uint;
+typedef unsigned char byte;
+
+struct HSV {
+	double h, s, v;
+};
+
+struct RGB {
+	byte r, g, b;
+};
+
+static struct RGB convert(struct HSV o) {
+	double c = o.v * o.s;
+	double h = o.h / 60.0;
+	double x = c * (1.0 - fabs(fmod(h, 2.0) - 1.0));
+	double m = o.v - c;
+	double r = m, g = m, b = m;
+	if      (h <= 1.0) { r += c; g += x; }
+	else if (h <= 2.0) { r += x; g += c; }
+	else if (h <= 3.0) { g += c; b += x; }
+	else if (h <= 4.0) { g += x; b += c; }
+	else if (h <= 5.0) { r += x; b += c; }
+	else if (h <= 6.0) { r += c; b += x; }
+	return (struct RGB) { r * 255.0, g * 255.0, b * 255.0 };
+}
+
+static const struct HSV
+R = {   0.0, 1.0, 1.0 },
+Y = {  60.0, 1.0, 1.0 },
+G = { 120.0, 1.0, 1.0 },
+C = { 180.0, 1.0, 1.0 },
+B = { 240.0, 1.0, 1.0 },
+M = { 300.0, 1.0, 1.0 };
+
+static struct HSV x(struct HSV o, double hd, double sf, double vf) {
+	return (struct HSV) {
+		fmod(o.h + hd, 360.0),
+		fmin(o.s * sf, 1.0),
+		fmin(o.v * vf, 1.0),
+	};
+}
+
+enum {
+	Black, Red, Green, Yellow, Blue, Magenta, Cyan, White,
+	Dark = 0,
+	Light = 8,
+	Background = 16,
+	Foreground,
+	Bold,
+	Selection,
+	Cursor,
+	SchemeLen,
+};
+static struct HSV scheme[SchemeLen];
+static struct HSV *dark = &scheme[Dark];
+static struct HSV *light = &scheme[Light];
+
+static void generate(void) {
+	light[Black]   = x(R, +45.0, 0.3, 0.3);
+	light[Red]     = x(R, +10.0, 0.9, 0.8);
+	light[Green]   = x(G, -55.0, 0.8, 0.6);
+	light[Yellow]  = x(Y, -20.0, 0.8, 0.8);
+	light[Blue]    = x(B, -55.0, 0.4, 0.5);
+	light[Magenta] = x(M, +45.0, 0.4, 0.6);
+	light[Cyan]    = x(C, -60.0, 0.3, 0.6);
+	light[White]   = x(R, +45.0, 0.3, 0.8);
+
+	dark[Black] = x(light[Black], 0.0, 1.0, 0.3);
+	dark[White] = x(light[White], 0.0, 1.0, 0.7);
+	for (uint i = Red; i < White; ++i) {
+		dark[i] = x(light[i], 0.0, 1.0, 0.8);
+	}
+
+	scheme[Background] = x(dark[Black],  0.0, 1.0, 0.9);
+	scheme[Foreground] = x(light[White], 0.0, 1.0, 0.9);
+	scheme[Bold]       = x(light[White], 0.0, 1.0, 1.0);
+	scheme[Selection]  = x(light[Red], +10.0, 1.0, 0.8);
+	scheme[Cursor]     = x(dark[White],  0.0, 1.0, 0.8);
+}
+
+static void swap(struct HSV *a, struct HSV *b) {
+	struct HSV c = *a;
+	*a = *b;
+	*b = c;
+}
+
+static void invert(void) {
+	swap(&dark[Black], &light[White]);
+	swap(&dark[White], &light[Black]);
+}
+
+typedef void OutputFn(const struct HSV *hsv, uint len);
+
+static void outputHSV(const struct HSV *hsv, uint len) {
+	for (uint i = 0; i < len; ++i) {
+		printf("%g,%g,%g\n", hsv[i].h, hsv[i].s, hsv[i].v);
+	}
+}
+
+#define FORMAT_RGB "%02hhX%02hhX%02hhX"
+
+static void outputRGB(const struct HSV *hsv, uint len) {
+	for (uint i = 0; i < len; ++i) {
+		struct RGB rgb = convert(hsv[i]);
+		printf(FORMAT_RGB "\n", rgb.r, rgb.g, rgb.b);
+	}
+}
+
+static void outputLinux(const struct HSV *hsv, uint len) {
+	for (uint i = 0; i < len; ++i) {
+		struct RGB rgb = convert(hsv[i]);
+		printf("\x1B]P%X" FORMAT_RGB, i, rgb.r, rgb.g, rgb.b);
+	}
+}
+
+static const char *Enum[SchemeLen] = {
+	"DarkBlack", "DarkRed", "DarkGreen", "DarkYellow",
+	"DarkBlue", "DarkMagenta", "DarkCyan", "DarkWhite",
+	"LightBlack", "LightRed", "LightGreen", "LightYellow",
+	"LightBlue", "LightMagenta", "LightCyan", "LightWhite",
+	"Background", "Foreground", "Bold", "Selection", "Cursor",
+};
+
+static void outputEnum(const struct HSV *hsv, uint len) {
+	printf("enum {\n");
+	for (uint i = 0; i < len; ++i) {
+		struct RGB rgb = convert(hsv[i]);
+		printf("\t%s = 0x" FORMAT_RGB ",\n", Enum[i], rgb.r, rgb.g, rgb.b);
+	}
+	printf("};\n");
+}
+
+static const char *Mintty[SchemeLen] = {
+	"Black", "Red", "Green", "Yellow",
+	"Blue", "Magenta", "Cyan", "White",
+	"BoldBlack", "BoldRed", "BoldGreen", "BoldYellow",
+	"BoldBlue", "BoldMagenta", "BoldCyan", "BoldWhite",
+	[Background] = "BackgroundColour",
+	[Foreground] = "ForegroundColour",
+	[Cursor]     = "CursorColour",
+};
+
+static void outputMintty(const struct HSV *hsv, uint len) {
+	for (uint i = 0; i < len; ++i) {
+		if (!Mintty[i]) continue;
+		struct RGB rgb = convert(hsv[i]);
+		printf("%s=%hhu,%hhu,%hhu\n", Mintty[i], rgb.r, rgb.g, rgb.b);
+	}
+}
+
+static void outputCSS(const struct HSV *hsv, uint len) {
+	printf(":root {\n");
+	for (uint i = 0; i < len; ++i) {
+		struct RGB rgb = convert(hsv[i]);
+		printf("\t--ansi%u: #" FORMAT_RGB ";\n", i, rgb.r, rgb.g, rgb.b);
+	}
+	printf("}\n");
+	for (uint i = 0; i < len; ++i) {
+		printf(
+			".fg%u { color: var(--ansi%u); }\n"
+			".bg%u { background-color: var(--ansi%u); }\n",
+			i, i, i, i
+		);
+	}
+}
+
+enum {
+	SwatchWidth = 64,
+	SwatchHeight = 64,
+	SwatchCols = 8,
+};
+
+static void outputPNG(const struct HSV *hsv, uint len) {
+	uint rows = (len + SwatchCols - 1) / SwatchCols;
+	uint width = SwatchWidth * SwatchCols;
+	uint height = SwatchHeight * rows;
+	pngHead(stdout, width, height, 8, PNGIndexed);
+
+	struct RGB pal[len];
+	for (uint i = 0; i < len; ++i) {
+		pal[i] = convert(hsv[i]);
+	}
+	pngPalette(stdout, (byte *)pal, sizeof(pal));
+
+	byte data[height][1 + width];
+	memset(data, 0, sizeof(data));
+	for (uint y = 0; y < height; ++y) {
+		data[y][0] = (y % SwatchHeight ? PNGUp : PNGSub);
+	}
+	for (uint i = 0; i < len; ++i) {
+		uint y = SwatchHeight * (i / SwatchCols);
+		uint x = SwatchWidth * (i % SwatchCols);
+		data[y][1 + x] = (x ? 1 : i);
+	}
+	pngData(stdout, (byte *)data, sizeof(data));
+	pngTail(stdout);
+}
+
+int main(int argc, char *argv[]) {
+	generate();
+
+	OutputFn *output = outputRGB;
+	const struct HSV *hsv = scheme;
+	uint len = 16;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "acghilmp:stx"))) {
+		switch (opt) {
+			break; case 'a': len = 16;
+			break; case 'c': output = outputEnum;
+			break; case 'g': output = outputPNG;
+			break; case 'h': output = outputHSV;
+			break; case 'i': invert();
+			break; case 'l': output = outputLinux;
+			break; case 'm': output = outputMintty;
+			break; case 'p': {
+				uint p = strtoul(optarg, NULL, 0);
+				if (p >= SchemeLen) return EX_USAGE;
+				hsv = &scheme[p];
+				len = 1;
+			}
+			break; case 's': output = outputCSS;
+			break; case 't': len = SchemeLen;
+			break; case 'x': output = outputRGB;
+			break; default:  return EX_USAGE;
+		}
+	}
+
+	output(hsv, len);
+}
diff --git a/bin/shotty.c b/bin/shotty.c
new file mode 100644
index 00000000..83b00313
--- /dev/null
+++ b/bin/shotty.c
@@ -0,0 +1,648 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <err.h>
+#include <locale.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <wchar.h>
+
+#define BIT(x) x##Bit, x = 1 << x##Bit, x##Bit_ = x##Bit
+
+typedef unsigned uint;
+
+enum {
+	NUL, SOH, STX, ETX, EOT, ENQ, ACK, BEL,
+	BS, HT, NL, VT, NP, CR, SO, SI,
+	DLE, DC1, DC2, DC3, DC4, NAK, SYN, ETB,
+	CAN, EM, SUB, ESC, FS, GS, RS, US,
+	DEL = 0x7F,
+};
+
+enum Attr {
+	BIT(Bold),
+	BIT(Dim),
+	BIT(Italic),
+	BIT(Underline),
+	BIT(Blink),
+	BIT(Reverse),
+};
+
+struct Style {
+	enum Attr attr;
+	int bg, fg;
+};
+
+struct Cell {
+	struct Style style;
+	wchar_t ch;
+};
+
+static uint rows = 24, cols = 80;
+static struct Cell *cells;
+
+static struct Cell *cell(uint y, uint x) {
+	assert(y <= rows);
+	assert(x <= cols);
+	assert(y * cols + x <= rows * cols);
+	return &cells[y * cols + x];
+}
+
+static uint y, x;
+static struct Style style = { .bg = -1, .fg = -1 };
+
+static struct {
+	uint y, x;
+} save;
+
+enum { ParamCap = 16 };
+static struct {
+	uint s[ParamCap];
+	uint n, i;
+} param;
+
+static uint p(uint i, uint z) {
+	return (i < param.n ? param.s[i] : z);
+}
+
+static uint min(uint a, uint b) {
+	return (a < b ? a : b);
+}
+
+#define _ch ch __attribute__((unused))
+typedef void Action(wchar_t ch);
+
+static void nop(wchar_t _ch) {
+}
+
+static void csi(wchar_t _ch) {
+	memset(&param, 0, sizeof(param));
+}
+
+static void csiSep(wchar_t _ch) {
+	if (param.n == ParamCap) return;
+	if (!param.n) param.n++;
+	param.n++;
+	param.i++;
+}
+
+static void csiDigit(wchar_t ch) {
+	param.s[param.i] *= 10;
+	param.s[param.i] += ch - L'0';
+	if (!param.n) param.n++;
+}
+
+static void bs(wchar_t _ch)  { if (x) x--; }
+static void ht(wchar_t _ch)  { x = min(x - x % 8 + 8, cols - 1); }
+static void cr(wchar_t _ch)  { x = 0; }
+static void cuu(wchar_t _ch) { y -= min(p(0, 1), y); }
+static void cud(wchar_t _ch) { y  = min(y + p(0, 1), rows - 1); }
+static void cuf(wchar_t _ch) { x  = min(x + p(0, 1), cols - 1); }
+static void cub(wchar_t _ch) { x -= min(p(0, 1), x); }
+static void cnl(wchar_t _ch) { x = 0; cud(0); }
+static void cpl(wchar_t _ch) { x = 0; cuu(0); }
+static void cha(wchar_t _ch) { x = min(p(0, 1) - 1, cols - 1); }
+static void vpa(wchar_t _ch) { y = min(p(0, 1) - 1, rows - 1); }
+static void cup(wchar_t _ch) {
+	y = min(p(0, 1) - 1, rows - 1);
+	x = min(p(1, 1) - 1, cols - 1);
+}
+static void decsc(wchar_t _ch) {
+	save.y = y;
+	save.x = x;
+}
+static void decrc(wchar_t _ch) {
+	y = save.y;
+	x = save.x;
+}
+
+static void move(struct Cell *dst, struct Cell *src, size_t len) {
+	memmove(dst, src, sizeof(*dst) * len);
+}
+
+static void erase(struct Cell *at, struct Cell *to) {
+	for (; at < to; ++at) {
+		at->style = style;
+		at->ch = L' ';
+	}
+}
+
+static void ed(wchar_t _ch) {
+	erase(
+		(p(0, 0) == 0 ? cell(y, x) : cell(0, 0)),
+		(p(0, 0) == 1 ? cell(y, x) : cell(rows - 1, cols))
+	);
+}
+static void el(wchar_t _ch) {
+	erase(
+		(p(0, 0) == 0 ? cell(y, x) : cell(y, 0)),
+		(p(0, 0) == 1 ? cell(y, x) : cell(y, cols))
+	);
+}
+static void ech(wchar_t _ch) {
+	erase(cell(y, x), cell(y, min(x + p(0, 1), cols)));
+}
+
+static void dch(wchar_t _ch) {
+	uint n = min(p(0, 1), cols - x);
+	move(cell(y, x), cell(y, x + n), cols - x - n);
+	erase(cell(y, cols - n), cell(y, cols));
+}
+static void ich(wchar_t _ch) {
+	uint n = min(p(0, 1), cols - x);
+	move(cell(y, x + n), cell(y, x), cols - x - n);
+	erase(cell(y, x), cell(y, x + n));
+}
+
+static struct {
+	uint top, bot;
+} scroll;
+
+static void scrollUp(uint top, uint n) {
+	n = min(n, scroll.bot - top);
+	move(cell(top, 0), cell(top + n, 0), cols * (scroll.bot - top - n));
+	erase(cell(scroll.bot - n, 0), cell(scroll.bot, 0));
+}
+
+static void scrollDown(uint top, uint n) {
+	n = min(n, scroll.bot - top);
+	move(cell(top + n, 0), cell(top, 0), cols * (scroll.bot - top - n));
+	erase(cell(top, 0), cell(top + n, 0));
+}
+
+static void decstbm(wchar_t _ch) {
+	scroll.bot = min(p(1, rows), rows);
+	scroll.top = min(p(0, 1) - 1, scroll.bot);
+}
+
+static void su(wchar_t _ch) { scrollUp(scroll.top, p(0, 1)); }
+static void sd(wchar_t _ch) { scrollDown(scroll.top, p(0, 1)); }
+static void dl(wchar_t _ch) { scrollUp(min(y, scroll.bot), p(0, 1)); }
+static void il(wchar_t _ch) { scrollDown(min(y, scroll.bot), p(0, 1)); }
+
+static void nl(wchar_t _ch) {
+	if (y + 1 == scroll.bot) {
+		scrollUp(scroll.top, 1);
+	} else {
+		y = min(y + 1, rows - 1);
+	}
+}
+static void ri(wchar_t _ch) {
+	if (y == scroll.top) {
+		scrollDown(scroll.top, 1);
+	} else {
+		if (y) y--;
+	}
+}
+
+static enum Mode {
+	BIT(Insert),
+	BIT(Wrap),
+	BIT(Cursor),
+} mode = Wrap | Cursor;
+
+static enum Mode paramMode(void) {
+	enum Mode mode = 0;
+	for (uint i = 0; i < param.n; ++i) {
+		switch (param.s[i]) {
+			break; case 4: mode |= Insert;
+			break; default: warnx("unhandled SM/RM %u", param.s[i]);
+		}
+	}
+	return mode;
+}
+
+static enum Mode paramDECMode(void) {
+	enum Mode mode = 0;
+	for (uint i = 0; i < param.n; ++i) {
+		switch (param.s[i]) {
+			break; case 1: // DECCKM
+			break; case 7: mode |= Wrap;
+			break; case 12: // "Start Blinking Cursor"
+			break; case 25: mode |= Cursor;
+			break; default: {
+				if (param.s[i] < 1000) {
+					warnx("unhandled DECSET/DECRST %u", param.s[i]);
+				}
+			}
+		}
+	}
+	return mode;
+}
+
+static void sm(wchar_t _ch) { mode |= paramMode(); }
+static void rm(wchar_t _ch) { mode &= ~paramMode(); }
+static void decset(wchar_t _ch) { mode |= paramDECMode(); }
+static void decrst(wchar_t _ch) { mode &= ~paramDECMode(); }
+
+enum {
+	Reset,
+	SetBold,
+	SetDim,
+	SetItalic,
+	SetUnderline,
+	SetBlink,
+	SetReverse = 7,
+
+	UnsetBoldDim = 22,
+	UnsetItalic,
+	UnsetUnderline,
+	UnsetBlink,
+	UnsetReverse = 27,
+
+	SetFg0 = 30,
+	SetFg7 = 37,
+	SetFg,
+	ResetFg,
+	SetBg0 = 40,
+	SetBg7 = 47,
+	SetBg,
+	ResetBg,
+
+	SetFg8 = 90,
+	SetFgF = 97,
+	SetBg8 = 100,
+	SetBgF = 107,
+
+	Color256 = 5,
+};
+
+static void sgr(wchar_t _ch) {
+	uint n = param.i + 1;
+	for (uint i = 0; i < n; ++i) {
+		switch (param.s[i]) {
+			break; case Reset: style = (struct Style) { .bg = -1, .fg = -1 };
+
+			break; case SetBold:      style.attr |= Bold; style.attr &= ~Dim;
+			break; case SetDim:       style.attr |= Dim; style.attr &= ~Bold;
+			break; case SetItalic:    style.attr |= Italic;
+			break; case SetUnderline: style.attr |= Underline;
+			break; case SetBlink:     style.attr |= Blink;
+			break; case SetReverse:   style.attr |= Reverse;
+
+			break; case UnsetBoldDim:   style.attr &= ~(Bold | Dim);
+			break; case UnsetItalic:    style.attr &= ~Italic;
+			break; case UnsetUnderline: style.attr &= ~Underline;
+			break; case UnsetBlink:     style.attr &= ~Blink;
+			break; case UnsetReverse:   style.attr &= ~Reverse;
+
+			break; case SetFg: {
+				if (++i < n && param.s[i] == Color256) {
+					if (++i < n) style.fg = param.s[i];
+				}
+			}
+			break; case SetBg: {
+				if (++i < n && param.s[i] == Color256) {
+					if (++i < n) style.bg = param.s[i];
+				}
+			}
+
+			break; case ResetFg: style.fg = -1;
+			break; case ResetBg: style.bg = -1;
+
+			break; default: {
+				uint p = param.s[i];
+				if (p >= SetFg0 && p <= SetFg7) {
+					style.fg = p - SetFg0;
+				} else if (p >= SetBg0 && p <= SetBg7) {
+					style.bg = p - SetBg0;
+				} else if (p >= SetFg8 && p <= SetFgF) {
+					style.fg = 8 + p - SetFg8;
+				} else if (p >= SetBg8 && p <= SetBgF) {
+					style.bg = 8 + p - SetBg8;
+				} else {
+					warnx("unhandled SGR %u", p);
+				}
+			}
+		}
+	}
+}
+
+static enum {
+	USASCII,
+	DECSpecial,
+} charset;
+
+static void usascii(wchar_t _ch) { charset = USASCII; }
+static void decSpecial(wchar_t _ch) { charset = DECSpecial; }
+
+static const wchar_t AltCharset[128] = {
+	['`'] = L'◆', ['a'] = L'▒', ['f'] = L'°', ['g'] = L'±', ['i'] = L'␋',
+	['j'] = L'┘', ['k'] = L'┐', ['l'] = L'┌', ['m'] = L'└', ['n'] = L'┼',
+	['o'] = L'⎺', ['p'] = L'⎻', ['q'] = L'─', ['r'] = L'⎼', ['s'] = L'⎽',
+	['t'] = L'├', ['u'] = L'┤', ['v'] = L'┴', ['w'] = L'┬', ['x'] = L'│',
+	['y'] = L'≤', ['z'] = L'≥', ['{'] = L'π', ['|'] = L'≠', ['}'] = L'£',
+	['~'] = L'·',
+};
+
+static void add(wchar_t ch) {
+	if (charset == DECSpecial && ch < 128 && AltCharset[ch]) {
+		ch = AltCharset[ch];
+	}
+
+	int width = wcwidth(ch);
+	if (width < 0) {
+		warnx("unhandled \\u%02X", ch);
+		return;
+	}
+
+	if (mode & Insert) {
+		uint n = min(width, cols - x);
+		move(cell(y, x + n), cell(y, x), cols - x - n);
+	}
+	if (mode & Wrap && x + width > cols) {
+		cr(0);
+		nl(0);
+	}
+
+	cell(y, x)->style = style;
+	cell(y, x)->ch = ch;
+	for (int i = 1; i < width && x + i < cols; ++i) {
+		cell(y, x + i)->style = style;
+		cell(y, x + i)->ch = L'\0';
+	}
+	x = min(x + width, (mode & Wrap ? cols : cols - 1));
+}
+
+static void html(void);
+static void mc(wchar_t _ch) {
+	if (p(0, 0) == 10) {
+		html();
+	} else {
+		warnx("unhandled CSI %u MC", p(0, 0));
+	}
+}
+
+static enum {
+	Data,
+	Esc,
+	G0,
+	CSI,
+	CSILt,
+	CSIEq,
+	CSIGt,
+	CSIQm,
+	CSIInter,
+	OSC,
+	OSCEsc,
+} state;
+
+static void escDefault(wchar_t ch) {
+	warnx("unhandled ESC %lc", ch);
+}
+
+static void g0Default(wchar_t ch) {
+	warnx("unhandled G0 %lc", ch);
+	charset = USASCII;
+}
+
+static void csiInter(wchar_t ch) {
+	switch (state) {
+		break; case CSI: warnx("unhandled CSI %lc ...", ch);
+		break; case CSILt: warnx("unhandled CSI < %lc ...", ch);
+		break; case CSIEq: warnx("unhandled CSI = %lc ...", ch);
+		break; case CSIGt: warnx("unhandled CSI > %lc ...", ch);
+		break; case CSIQm: warnx("unhandled CSI ? %lc ...", ch);
+		break; default: abort();
+	}
+}
+
+static void csiFinal(wchar_t ch) {
+	switch (state) {
+		break; case CSI: warnx("unhandled CSI %lc", ch);
+		break; case CSILt: warnx("unhandled CSI < %lc", ch);
+		break; case CSIEq: warnx("unhandled CSI = %lc", ch);
+		break; case CSIGt: warnx("unhandled CSI > %lc", ch);
+		break; case CSIQm: warnx("unhandled CSI ? %lc", ch);
+		break; case CSIInter: warnx("unhandled CSI ... %lc", ch);
+		break; default: abort();
+	}
+}
+
+#define S(s) break; case s: switch (ch)
+#define A(c, a, s) break; case c: a(ch); state = s
+#define D(a, s) break; default: a(ch); state = s
+static void update(wchar_t ch) {
+	switch (state) {
+		default: abort();
+
+		S(Data) {
+			A(BEL, nop, Data);
+			A(BS,  bs,  Data);
+			A(HT,  ht,  Data);
+			A(NL,  nl,  Data);
+			A(CR,  cr,  Data);
+			A(ESC, nop, Esc);
+			D(add, Data);
+		}
+
+		S(Esc) {
+			A('(', nop, G0);
+			A('7', decsc, Data);
+			A('8', decrc, Data);
+			A('=', nop, Data);
+			A('>', nop, Data);
+			A('M', ri,  Data);
+			A('[', csi, CSI);
+			A(']', nop, OSC);
+			D(escDefault, Data);
+		}
+		S(G0) {
+			A('0', decSpecial, Data);
+			A('B', usascii, Data);
+			D(g0Default, Data);
+		}
+
+		S(CSI) {
+			A(' ' ... '/', csiInter, CSIInter);
+			A('0' ... '9', csiDigit, CSI);
+			A(':', nop, CSI);
+			A(';', csiSep, CSI);
+			A('<', nop, CSILt);
+			A('=', nop, CSIEq);
+			A('>', nop, CSIGt);
+			A('?', nop, CSIQm);
+			A('@', ich, Data);
+			A('A', cuu, Data);
+			A('B', cud, Data);
+			A('C', cuf, Data);
+			A('D', cub, Data);
+			A('E', cnl, Data);
+			A('F', cpl, Data);
+			A('G', cha, Data);
+			A('H', cup, Data);
+			A('J', ed,  Data);
+			A('K', el,  Data);
+			A('L', il,  Data);
+			A('M', dl,  Data);
+			A('P', dch, Data);
+			A('S', su,  Data);
+			A('T', sd,  Data);
+			A('X', ech, Data);
+			A('d', vpa, Data);
+			A('h', sm,  Data);
+			A('i', mc,  Data);
+			A('l', rm,  Data);
+			A('m', sgr, Data);
+			A('r', decstbm, Data);
+			A('t', nop, Data);
+			D(csiFinal, Data);
+		}
+
+		S(CSILt ... CSIGt) {
+			A(' ' ... '/', csiInter, CSIInter);
+			A('0' ... '9', csiDigit, state);
+			A(':', nop, state);
+			A(';', csiSep, state);
+			D(csiFinal, Data);
+		}
+
+		S(CSIQm) {
+			A(' ' ... '/', csiInter, CSIInter);
+			A('0' ... '9', csiDigit, CSIQm);
+			A(':', nop, CSIQm);
+			A(';', csiSep, CSIQm);
+			A('h', decset, Data);
+			A('l', decrst, Data);
+			D(csiFinal, Data);
+		}
+
+		S(CSIInter) {
+			D(csiFinal, Data);
+		}
+
+		S(OSC) {
+			A(BEL, nop, Data);
+			A(ESC, nop, OSCEsc);
+			D(nop, OSC);
+		}
+		S(OSCEsc) {
+			A('\\', nop, Data);
+			D(nop, OSC);
+		}
+	}
+}
+
+static bool bright;
+static int defaultBg = 0;
+static int defaultFg = 7;
+
+static void span(const struct Style *prev, const struct Cell *cell) {
+	struct Style style = cell->style;
+	if (!prev || memcmp(prev, &style, sizeof(*prev))) {
+		if (prev) printf("</span>");
+		if (style.bg < 0) style.bg = defaultBg;
+		if (style.fg < 0) style.fg = defaultFg;
+		if (bright && style.attr & Bold) {
+			if (style.fg < 8) style.fg += 8;
+			style.attr ^= Bold;
+		}
+		printf(
+			"<span style=\"%s%s%s\" class=\"bg%u fg%u\">",
+			(style.attr & Bold ? "font-weight:bold;" : ""),
+			(style.attr & Italic ? "font-style:italic;" : ""),
+			(style.attr & Underline ? "text-decoration:underline;" : ""),
+			(style.attr & Reverse ? style.fg : style.bg),
+			(style.attr & Reverse ? style.bg : style.fg)
+		);
+	}
+	switch (cell->ch) {
+		break; case '&': printf("&amp;");
+		break; case '<': printf("&lt;");
+		break; case '>': printf("&gt;");
+		break; default:  printf("%lc", (wint_t)cell->ch);
+	}
+}
+
+static bool mediaCopy;
+static void html(void) {
+	mediaCopy = true;
+	if (mode & Cursor) cell(y, x)->style.attr ^= Reverse;
+	printf(
+		"<pre style=\"width: %uch;\" class=\"bg%u fg%u\">",
+		cols, defaultBg, defaultFg
+	);
+	for (uint y = 0; y < rows; ++y) {
+		for (uint x = 0; x < cols; ++x) {
+			if (!cell(y, x)->ch) continue;
+			span(x ? &cell(y, x - 1)->style : NULL, cell(y, x));
+		}
+		printf("</span>\n");
+	}
+	printf("</pre>\n");
+	if (mode & Cursor) cell(y, x)->style.attr ^= Reverse;
+}
+
+int main(int argc, char *argv[]) {
+	setlocale(LC_CTYPE, "");
+
+	bool debug = false;
+	bool size = false;
+	bool hide = false;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "Bb:df:h:nsw:"))) {
+		switch (opt) {
+			break; case 'B': bright = true;
+			break; case 'b': defaultBg = strtol(optarg, NULL, 0);
+			break; case 'd': debug = true;
+			break; case 'f': defaultFg = strtol(optarg, NULL, 0);
+			break; case 'h': rows = strtoul(optarg, NULL, 0);
+			break; case 'n': hide = true;
+			break; case 's': size = true;
+			break; case 'w': cols = strtoul(optarg, NULL, 0);
+			break; default:  return EX_USAGE;
+		}
+	}
+
+	FILE *file = stdin;
+	if (optind < argc) {
+		file = fopen(argv[optind], "r");
+		if (!file) err(EX_NOINPUT, "%s", argv[optind]);
+	}
+
+	if (size) {
+		struct winsize window;
+		int error = ioctl(STDERR_FILENO, TIOCGWINSZ, &window);
+		if (error) err(EX_IOERR, "ioctl");
+		rows = window.ws_row;
+		cols = window.ws_col;
+	}
+	scroll.bot = rows;
+
+	cells = calloc(rows * cols, sizeof(*cells));
+	if (!cells) err(EX_OSERR, "calloc");
+	erase(cell(0, 0), cell(rows - 1, cols));
+
+	wint_t ch;
+	while (WEOF != (ch = getwc(file))) {
+		uint prev = state;
+		update(ch);
+		if (debug && state != prev && state == Data) html();
+	}
+	if (ferror(file)) err(EX_IOERR, "getwc");
+
+	if (!mediaCopy) {
+		if (hide) mode &= ~Cursor;
+		html();
+	}
+}
diff --git a/bin/title.c b/bin/title.c
new file mode 100644
index 00000000..82f89d95
--- /dev/null
+++ b/bin/title.c
@@ -0,0 +1,211 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <curl/curl.h>
+#include <err.h>
+#include <locale.h>
+#include <regex.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <wchar.h>
+
+static regex_t regex(const char *pattern, int flags) {
+	regex_t regex;
+	int error = regcomp(&regex, pattern, REG_EXTENDED | flags);
+	if (!error) return regex;
+
+	char buf[256];
+	regerror(error, &regex, buf, sizeof(buf));
+	errx(EX_SOFTWARE, "regcomp: %s: %s", buf, pattern);
+}
+
+static const struct Entity {
+	wchar_t ch;
+	const char *name;
+} Entities[] = {
+	{ L'"', "&quot;" },
+	{ L'&', "&amp;" },
+	{ L'<', "&lt;" },
+	{ L'>', "&gt;" },
+	{ L'␤', "&#10;" },
+};
+
+static wchar_t entity(const char *name) {
+	for (size_t i = 0; i < sizeof(Entities) / sizeof(Entities[0]); ++i) {
+		struct Entity entity = Entities[i];
+		if (strncmp(name, entity.name, strlen(entity.name))) continue;
+		return entity.ch;
+	}
+	if (!strncmp(name, "&#x", 3)) return strtoul(&name[3], NULL, 16);
+	if (!strncmp(name, "&#", 2)) return strtoul(&name[2], NULL, 10);
+	return 0;
+}
+
+static const char EntityPattern[] = {
+	"[[:space:]]+|&([[:alpha:]]+|#([[:digit:]]+|x[[:xdigit:]]+));"
+};
+static regex_t EntityRegex;
+
+static void showTitle(const char *title) {
+	regmatch_t match = {0};
+	for (; *title; title += match.rm_eo) {
+		if (regexec(&EntityRegex, title, 1, &match, 0)) break;
+		if (title[match.rm_so] != '&') {
+			printf("%.*s ", (int)match.rm_so, title);
+			continue;
+		}
+		wchar_t ch = entity(&title[match.rm_so]);
+		if (ch) {
+			printf("%.*s%lc", (int)match.rm_so, title, (wint_t)ch);
+		} else {
+			printf("%.*s", (int)match.rm_eo, title);
+		}
+	}
+	printf("%s\n", title);
+}
+
+static CURL *curl;
+static bool title;
+static struct {
+	char buf[64 * 1024];
+	size_t len;
+} body;
+
+// HE COMES
+static const char TitlePattern[] = "<title>([^<]*)</title>";
+static regex_t TitleRegex;
+
+static size_t handleBody(char *buf, size_t size, size_t nitems, void *user) {
+	(void)user;
+	size_t len = size * nitems;
+	size_t cap = sizeof(body.buf) - body.len - 1;
+	size_t new = (len < cap ? len : cap);
+	if (title || !new) return len;
+
+	memcpy(&body.buf[body.len], buf, new);
+	body.len += new;
+	body.buf[body.len] = '\0';
+
+	regmatch_t match[2];
+	if (regexec(&TitleRegex, body.buf, 2, match, 0)) return len;
+	body.buf[match[1].rm_eo] = '\0';
+	showTitle(&body.buf[match[1].rm_so]);
+	title = true;
+
+	return len;
+}
+
+static CURLcode fetchTitle(const char *url) {
+	CURLcode code = curl_easy_setopt(curl, CURLOPT_URL, url);
+	if (code) return code;
+
+	curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
+	code = curl_easy_perform(curl);
+	if (code) return code;
+
+	char *type;
+	code = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &type);
+	if (code) return code;
+	if (!type || strncmp(type, "text/html", 9)) return CURLE_OK;
+
+	char *dest;
+	curl_easy_getinfo(curl, CURLINFO_EFFECTIVE_URL, &dest);
+	dest = strdup(dest);
+	if (!dest) err(EX_OSERR, "strdup");
+
+	code = curl_easy_setopt(curl, CURLOPT_URL, dest);
+	if (code) return code;
+	free(dest);
+
+	body.len = 0;
+	title = false;
+	curl_easy_setopt(curl, CURLOPT_HTTPGET, 1L);
+	code = curl_easy_perform(curl);
+	return code;
+}
+
+int main(int argc, char *argv[]) {
+	EntityRegex = regex(EntityPattern, 0);
+	TitleRegex = regex(TitlePattern, REG_ICASE);
+
+	setlocale(LC_CTYPE, "");
+	setlinebuf(stdout);
+
+	CURLcode code = curl_global_init(CURL_GLOBAL_ALL);
+	if (code) errx(EX_OSERR, "curl_global_init: %s", curl_easy_strerror(code));
+
+	curl = curl_easy_init();
+	if (!curl) errx(EX_SOFTWARE, "curl_easy_init");
+
+	static char error[CURL_ERROR_SIZE];
+	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, error);
+
+	curl_easy_setopt(curl, CURLOPT_PROTOCOLS, CURLPROTO_HTTP | CURLPROTO_HTTPS);
+	curl_easy_setopt(
+		curl, CURLOPT_USERAGENT,
+		"curl/7.54.0 facebookexternalhit/1.1 Twitterbot/1.0"
+	);
+	curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "");
+	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
+	curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 3L);
+	curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L);
+
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, handleBody);
+
+	bool exclude = false;
+	regex_t excludeRegex;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "x:v"))) {
+		switch (opt) {
+			break; case 'x': {
+				exclude = true;
+				excludeRegex = regex(optarg, REG_NOSUB);
+			}
+			break; case 'v': curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
+			break; default:  return EX_USAGE;
+		}
+	}
+
+	if (optind < argc) {
+		code = fetchTitle(argv[optind]);
+		if (!code) return EX_OK;
+		errx(EX_DATAERR, "curl_easy_perform: %s", error);
+	}
+
+	char *buf = NULL;
+	size_t cap = 0;
+
+	regex_t urlRegex = regex("https?://([^[:space:]>\"()]|[(][^)]*[)])+", 0);
+	while (0 < getline(&buf, &cap, stdin)) {
+		regmatch_t match = {0};
+		for (char *ptr = buf; *ptr; ptr += match.rm_eo) {
+			if (regexec(&urlRegex, ptr, 1, &match, 0)) break;
+			ptr[match.rm_eo] = '\0';
+			const char *url = &ptr[match.rm_so];
+			if (!exclude || regexec(&excludeRegex, url, 0, NULL, 0)) {
+				code = fetchTitle(url);
+				if (code) warnx("curl_easy_perform: %s", error);
+			}
+			ptr[match.rm_eo] = ' ';
+		}
+	}
+	if (ferror(stdin)) err(EX_IOERR, "getline");
+}
diff --git a/bin/ttpre.c b/bin/ttpre.c
new file mode 100644
index 00000000..4917be37
--- /dev/null
+++ b/bin/ttpre.c
@@ -0,0 +1,66 @@
+/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <wchar.h>
+
+static void put(wchar_t ch) {
+	switch (ch) {
+		break; case L'&': printf("&amp;");
+		break; case L'<': printf("&lt;");
+		break; case L'>': printf("&gt;");
+		break; default:   printf("%lc", (wint_t)ch);
+	}
+}
+
+static void tag(const char *open) {
+	static const char *close = NULL;
+	if (close == open) return;
+	if (close) printf("</%s>", close);
+	if (open) printf("<%s>", open);
+	close = open;
+}
+
+static void push(wchar_t ch) {
+	static wchar_t q[3];
+	if (q[1] == L'\b' && q[0] == L'_') {
+		tag("i");
+		put(q[2]);
+		q[0] = q[1] = q[2] = 0;
+	} else if (q[1] == L'\b' && q[0] == q[2]) {
+		tag("b");
+		put(q[2]);
+		q[0] = q[1] = q[2] = 0;
+	} else if (q[0]) {
+		tag(NULL);
+		put(q[0]);
+	}
+	q[0] = q[1];
+	q[1] = q[2];
+	q[2] = ch;
+}
+
+int main(void) {
+	setlocale(LC_CTYPE, "");
+	printf("<pre>");
+	wint_t ch;
+	while (WEOF != (ch = getwchar())) push(ch);
+	push(0); push(0); push(0);
+	printf("</pre>\n");
+	return EXIT_SUCCESS;
+}
diff --git a/bin/up.sh b/bin/up.sh
new file mode 100644
index 00000000..e65d4522
--- /dev/null
+++ b/bin/up.sh
@@ -0,0 +1,76 @@
+#!/bin/sh
+set -eu
+
+readonly Host='temp.causal.agency'
+
+upload() {
+	local src ext ts rand url
+	src=$1
+	ext=${src##*.}
+	ts=$(date +'%s')
+	rand=$(openssl rand -hex 4)
+	url=$(printf '%s/%x%s.%s' "$Host" "$ts" "$rand" "$ext")
+	scp -q "$src" "${Host}:/usr/local/www/${url}"
+	echo "https://${url}"
+}
+
+temp() {
+	temp=$(mktemp -d)
+	trap "rm -r '$temp'" EXIT
+}
+
+uploadText() {
+	temp
+	cat > "${temp}/input.txt"
+	upload "${temp}/input.txt"
+}
+
+uploadCommand() {
+	temp
+	echo "$ $*" > "${temp}/exec.txt"
+	"$@" >> "${temp}/exec.txt" 2>&1 || true
+	upload "${temp}/exec.txt"
+}
+
+uploadHi() {
+	temp
+	hi -f html -o document,anchor,tab=4 "$@" > "${temp}/hi.html"
+	upload "${temp}/hi.html"
+}
+
+uploadScreen() {
+	temp
+	screencapture -i "$@" "${temp}/capture.png"
+	pngo "${temp}/capture.png" || true
+	upload "${temp}/capture.png"
+}
+
+uploadTerminal() {
+	temp
+	cat > "${temp}/term.html" <<-EOF
+	<!DOCTYPE html>
+	<title>${1}</title>
+	<style>
+	$(scheme -s)
+	</style>
+	EOF
+	ptee "$@" | shotty -Bs >> "${temp}/term.html"
+	upload "${temp}/term.html"
+}
+
+while getopts 'chst' opt; do
+	case "$opt" in
+		(c) fn=uploadCommand;;
+		(h) fn=uploadHi;;
+		(s) fn=uploadScreen;;
+		(t) fn=uploadTerminal;;
+		(?) exit 1;;
+	esac
+done
+shift $((OPTIND - 1))
+[ $# -eq 0 ] && : ${fn:=uploadText}
+: ${fn:=upload}
+
+url=$($fn "$@")
+printf '%s' "$url" | pbcopy || true
+echo "$url"
diff --git a/bin/when.y b/bin/when.y
new file mode 100644
index 00000000..5367b3b3
--- /dev/null
+++ b/bin/when.y
@@ -0,0 +1,250 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+%{
+
+#include <ctype.h>
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <strings.h>
+#include <sysexits.h>
+#include <time.h>
+
+static void yyerror(const char *str);
+static int yylex(void);
+
+#define YYSTYPE struct tm
+
+static const char *Days[7] = {
+	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
+};
+
+static const char *Months[12] = {
+	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
+};
+
+static const struct tm Week = { .tm_mday = 7 };
+
+static struct tm normalize(struct tm date) {
+	time_t time = timegm(&date);
+	struct tm *norm = gmtime(&time);
+	if (!norm) err(EX_OSERR, "gmtime");
+	return *norm;
+}
+
+static struct tm today(void) {
+	time_t now = time(NULL);
+	struct tm *local = localtime(&now);
+	if (!local) err(EX_OSERR, "localtime");
+	struct tm date = {
+		.tm_year = local->tm_year,
+		.tm_mon = local->tm_mon,
+		.tm_mday = local->tm_mday,
+	};
+	return normalize(date);
+}
+
+static struct tm monthDay(int month, int day) {
+	struct tm date = today();
+	date.tm_mon = month;
+	date.tm_mday = day;
+	return normalize(date);
+}
+
+static struct tm monthDayYear(int month, int day, int year) {
+	struct tm date = today();
+	date.tm_mon = month;
+	date.tm_mday = day;
+	date.tm_year = year - 1900;
+	return normalize(date);
+}
+
+static struct tm weekDay(int day) {
+	struct tm date = today();
+	date.tm_mday += day - date.tm_wday;
+	return normalize(date);
+}
+
+static struct tm scalarAdd(struct tm a, struct tm b) {
+	a.tm_mday += b.tm_mday;
+	a.tm_mon += b.tm_mon;
+	a.tm_year += b.tm_year;
+	return a;
+}
+
+static struct tm scalarSub(struct tm a, struct tm b) {
+	a.tm_mday -= b.tm_mday;
+	a.tm_mon -= b.tm_mon;
+	a.tm_year -= b.tm_year;
+	return a;
+}
+
+static struct tm dateAdd(struct tm date, struct tm scalar) {
+	return normalize(scalarAdd(date, scalar));
+}
+
+static struct tm dateSub(struct tm date, struct tm scalar) {
+	return normalize(scalarSub(date, scalar));
+}
+
+static struct tm dateDiff(struct tm a, struct tm b) {
+	struct tm diff = {
+		.tm_year = a.tm_year - b.tm_year,
+		.tm_mon = a.tm_mon - b.tm_mon,
+		.tm_mday = a.tm_mday - b.tm_mday,
+	};
+	if (a.tm_mon < b.tm_mon) {
+		diff.tm_year--;
+		diff.tm_mon += 12;
+	}
+	if (a.tm_mday < b.tm_mday) {
+		diff.tm_mon--;
+		diff.tm_mday = 0;
+		while (dateAdd(b, diff).tm_mday != a.tm_mday) diff.tm_mday++;
+	}
+	time_t atime = timegm(&a), btime = timegm(&b);
+	diff.tm_yday = (atime - btime) / 24 / 60 / 60;
+	return diff;
+}
+
+static void printDate(struct tm date) {
+	printf(
+		"%s %s %d %d\n",
+		Days[date.tm_wday], Months[date.tm_mon],
+		date.tm_mday, 1900 + date.tm_year
+	);
+}
+
+static void printScalar(struct tm scalar) {
+	if (scalar.tm_year) printf("%dy ", scalar.tm_year);
+	if (scalar.tm_mon) printf("%dm ", scalar.tm_mon);
+	if (scalar.tm_mday % 7) {
+		printf("%dd ", scalar.tm_mday);
+	} else if (scalar.tm_mday) {
+		printf("%dw ", scalar.tm_mday / 7);
+	}
+	if (scalar.tm_yday && scalar.tm_mon) printf("(%dd) ", scalar.tm_yday);
+	printf("\n");
+}
+
+%}
+
+%token Number Month Day
+%left '+' '-'
+%right '<' '>'
+
+%%
+
+expr:
+	date { printDate($1); }
+	| scalar { printScalar($1); }
+	;
+
+date:
+	dateLit
+	| '(' date ')' { $$ = $2; }
+	| '<' date { $$ = dateSub($2, Week); }
+	| '>' date { $$ = dateAdd($2, Week); }
+	| date '+' scalar { $$ = dateAdd($1, $3); }
+	| date '-' scalar { $$ = dateSub($1, $3); }
+	;
+
+scalar:
+	scalarLit
+	| '(' scalar ')' { $$ = $2; }
+	| scalar '+' scalar { $$ = scalarAdd($1, $3); }
+	| scalar '-' scalar { $$ = scalarSub($1, $3); }
+	| date '-' date { $$ = dateDiff($1, $3); }
+	;
+
+dateLit:
+	{ $$ = today(); }
+	| '.' { $$ = today(); }
+	| Month Number { $$ = monthDay($1.tm_mon, $2.tm_sec); }
+	| Month Number Number { $$ = monthDayYear($1.tm_mon, $2.tm_sec, $3.tm_sec); }
+	| Day { $$ = weekDay($1.tm_wday); }
+	;
+
+scalarLit:
+	Number 'd' { $$ = (struct tm) { .tm_mday = $1.tm_sec }; }
+	| Number 'w' { $$ = (struct tm) { .tm_mday = 7 * $1.tm_sec }; }
+	| Number 'm' { $$ = (struct tm) { .tm_mon = $1.tm_sec }; }
+	| Number 'y' { $$ = (struct tm) { .tm_year = $1.tm_sec }; }
+	;
+
+%%
+
+static void yyerror(const char *str) {
+	warnx("%s", str);
+}
+
+static const char *input;
+
+static int yylex(void) {
+	while (isspace(*input)) input++;
+	if (!*input) return EOF;
+
+	if (isdigit(*input)) {
+		char *rest;
+		yylval.tm_sec = strtol(input, &rest, 10);
+		input = rest;
+		return Number;
+	}
+
+	for (int i = 0; i < 7; ++i) {
+		if (strncasecmp(input, Days[i], 3)) continue;
+		while (isalpha(*input)) input++;
+		yylval.tm_wday = i;
+		return Day;
+	}
+
+	for (int i = 0; i < 12; ++i) {
+		if (strncasecmp(input, Months[i], 3)) continue;
+		while (isalpha(*input)) input++;
+		yylval.tm_mon = i;
+		return Month;
+	}
+
+	return *input++;
+}
+
+int main(int argc, char *argv[]) {
+	if (argc > 1) {
+		input = argv[1];
+		return yyparse();
+	}
+
+	struct tm date = today();
+	printDate(date);
+	printf("\n");
+
+	char *line = NULL;
+	size_t cap = 0;
+	while (0 < getline(&line, &cap, stdin)) {
+		if (line[0] == '\n') continue;
+
+		if (today().tm_mday != date.tm_mday) {
+			warnx("the date has changed");
+			date = today();
+		}
+
+		input = line;
+		yyparse();
+		printf("\n");
+	}
+}
diff --git a/bin/xx.c b/bin/xx.c
new file mode 100644
index 00000000..6d04f2f5
--- /dev/null
+++ b/bin/xx.c
@@ -0,0 +1,142 @@
+/* Copyright (C) 2017  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <ctype.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+typedef unsigned char byte;
+
+static bool zero(const byte *ptr, size_t size) {
+	for (size_t i = 0; i < size; ++i) {
+		if (ptr[i]) return false;
+	}
+	return true;
+}
+
+static struct {
+	size_t cols;
+	size_t group;
+	size_t blank;
+	bool ascii;
+	bool offset;
+	bool skip;
+} options = { 16, 8, 0, true, true, false };
+
+static void dump(FILE *file) {
+	bool skip = false;
+
+	byte buf[options.cols];
+	size_t offset = 0;
+	for (
+		size_t size;
+		(size = fread(buf, 1, sizeof(buf), file));
+		offset += size
+	) {
+		if (options.skip) {
+			if (zero(buf, size)) {
+				if (!skip) printf("*\n");
+				skip = true;
+				continue;
+			} else {
+				skip = false;
+			}
+		}
+
+		if (options.blank) {
+			if (offset && offset % options.blank == 0) {
+				printf("\n");
+			}
+		}
+
+		if (options.offset) {
+			printf("%08zX:  ", offset);
+		}
+
+		for (size_t i = 0; i < sizeof(buf); ++i) {
+			if (options.group) {
+				if (i && !(i % options.group)) {
+					printf(" ");
+				}
+			}
+			if (i < size) {
+				printf("%02hhX ", buf[i]);
+			} else {
+				printf("   ");
+			}
+		}
+
+		if (options.ascii) {
+			printf(" ");
+			for (size_t i = 0; i < size; ++i) {
+				if (options.group) {
+					if (i && !(i % options.group)) {
+						printf(" ");
+					}
+				}
+				printf("%c", isprint(buf[i]) ? buf[i] : '.');
+			}
+		}
+
+		printf("\n");
+	}
+}
+
+static void undump(FILE *file) {
+	byte c;
+	int match;
+	while (0 < (match = fscanf(file, " %hhx", &c))) {
+		printf("%c", c);
+	}
+	if (!match) errx(EX_DATAERR, "invalid input");
+}
+
+int main(int argc, char *argv[]) {
+	bool reverse = false;
+	const char *path = NULL;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "ac:g:p:rsz"))) {
+		switch (opt) {
+			break; case 'a': options.ascii ^= true;
+			break; case 'c': options.cols = strtoul(optarg, NULL, 0);
+			break; case 'g': options.group = strtoul(optarg, NULL, 0);
+			break; case 'p': options.blank = strtoul(optarg, NULL, 0);
+			break; case 'r': reverse = true;
+			break; case 's': options.offset ^= true;
+			break; case 'z': options.skip ^= true;
+			break; default: return EX_USAGE;
+		}
+	}
+	if (argc > optind) path = argv[optind];
+	if (!options.cols) return EX_USAGE;
+
+	FILE *file = path ? fopen(path, "r") : stdin;
+	if (!file) err(EX_NOINPUT, "%s", path);
+
+	if (reverse) {
+		undump(file);
+	} else {
+		dump(file);
+	}
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+
+	return EX_OK;
+}