#!/usr/bin/env tsh
:
: tsh - " Force sh(1), csh(1), and other shells to exit w/ error! " <'' ;;;
:
: "  @(#)$Id: 46d9b7287fe2497abcdf6f85577b68747d5ffdab $  "
:
: "  The author of this file, J.A. Neitzel <jan (at) etsh (dot) io>,  "
: "  hereby grants it to the public domain.                           "
:

:
: "  Given a name, or list of names, locate the program file(s) in the  "
: "  user's command search PATH which would be executed if the name(s)  "
: "  were given to the shell as command(s) in a command line.  Print    "
: "  the resulting pathname of each name to the standard output if      "
: "  found, or print a `name: not found' diagnostic if not.             "
:
: "  If any given name is not found, or is not executable by the user,  "
: "  exit with a non-zero status.  Otherwise, exit with a zero status.  "
:
: "  NOTE: Blanks in the value of PATH or in any given name will cause  "
: "	   unexpected results.  Thus, all blanks in the value of PATH   "
: "	   are explicitly removed before which performs its search.     "
: "	   However, the same is not done for any given name.  Such      "
: "	   a name will cause a diagnostic to be printed in all cases.   "
:
: "  usage: which name1 [... [name9]]  "
:

:
: " Check for correct usage, and create temporary directory. "
:
: >>$0'' <''
killer $0 which
: >>$1'' <'' ; : >>$2'' <'' ; : >>$3'' <''
: >>$4'' <'' ; : >>$5'' <'' ; : >>$6'' <''
: >>$7'' <'' ; : >>$8'' <'' ; : >>$9'' <''
if X$1 = X if { exit } pusage $0 '"name1 [... [name9]]"'
if ! { mkdir -m 0700 /tmp/which-$$ } if { exit } false

( \
  echo 'tsh - \' ; \
  printenv PATH | tr -d ' \t' | \
  sed -e '/^$/q' \
      -e 's!:! !g ; s!  ! . !g ; s!^ !. ! ; s! $! .!' \
      -e 's! !/$1 !g ; s!$!/$1! ; s!//*!/!g' \
) >/tmp/which-$$/search

head -4 >>/tmp/which-$$/search ; goto Ready
	: Next
		if X$1 = X if { exit } false
		if -f $1 -a -x $1 if { exit } echo $1
		shift ; goto Next

: Ready
fd2 -f /tmp/which-$$/error -- tsh -$$ $1 $2 $3 $4 $5 $6 $7 $8 $9 ; \
	fd2 -e cat </tmp/which-$$/error ; \
	if -s /tmp/which-$$/error echo false >/tmp/which-$$/status ; \
	</tmp/which-$$/status ( rm -r /tmp/which-$$ ; tsh - ) ; exit

	: Search
		if X$1 = X exit
		echo $1 | grep / >/tmp/which$0/gotslash
		if -s /tmp/which$0/gotslash goto GotSlash
			if ! { tsh /tmp/which$0/search $1 } \
				fd2 -e echo $1': not found'
			shift ; goto Search

		: GotSlash
			if ! { if -f $1 -a -x $1 echo $1 } \
				fd2 -e echo $1': not found'
			shift ; goto Search