/usr/share/doc/bash/examples/functions/coproc.bash is in bash-doc 4.2+dfsg-0.1+deb7u3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 | # coprocess.bash
#
# vi:set sts=2 sw=2 ai:
#
coprocess_pid=
#
# coprocess - Start, control, and end coprocesses.
#
function coprocess ()
{
while (( $# > 0 )) ; do
case "$1" in
#
# coprocess close
#
c|cl|clo|clos|close)
shift
exec 61>&- 62<&-
coprocess_pid=
if [ "$1" = "-SIGPIPE" ] ; then
# Only print message in an interactive shell
case "$-" in
*i*)
echo 'SIGPIPE' >&2
;;
esac
return 1
fi
return 0
;;
#
# coprocess open
#
o|op|ope|open)
shift
local fifo="/var/tmp/coprocess.$$.$RANDOM"
local cmd="/bin/bash"
if (( $# > 0 )) ; then
cmd="$@"
fi
mkfifo "$fifo.in" || return $?
mkfifo "$fifo.out" || {
ret=$?
rm -f "$fifo.in"
return $?
}
( "$@" <$fifo.in >$fifo.out ; rm -f "$fifo.in" "$fifo.out" ) &
coprocess_pid=$!
exec 61>$fifo.in 62<$fifo.out
return 0
;;
#
# coprocess print - write to the coprocess
#
p|pr|pri|prin|print)
shift
local old_trap=$(trap -p SIGPIPE)
trap 'coprocess close -SIGPIPE' SIGPIPE
if [ $# -eq 1 ] && [ "$1" = "--stdin" ] ; then
cat >&61
else
echo "$@" >&61
fi
local ret=$?
eval "$old_trap"
return $ret
;;
#
# coprocess read - read from the coprocess
#
r|re|rea|read)
shift
local old_trap=$(trap -p SIGPIPE)
trap '_coprocess_close -SIGPIPE' SIGPIPE
builtin read "$@" <&62
local ret=$?
eval "$old_trap"
return $ret
;;
s|st|sta|stat|statu|status)
if [ -z "$coprocess_pid" ] ; then
echo 'no active coprocess'
return 1
else
echo " coprocess is active [$coprocess_pid]"
return 0
fi
;;
*)
coprocess print "$@"
return $?
;;
esac
shift
done
coprocess status
return $?
}
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