fg/bg: run command in background with user notification

[Brandon S. Allbery]

Yet another attempt to put the sources back into alt.sources....

This is a little script that I've been using in various forms for a couple
of years now, on a number of System III/V systems.  It's a variant of nohup;
it runs a command in the background and saves its output.  There are three
differences from nohup, however:

* it notifies the user upon command completion by ringing the terminal
  bell:  twice if no error, 3 times if error

* on VT100-compatible terminals which have or emulate the keyboard LEDs,
  it can inform the user of command completion using them:  L1 is on while
  the program is running, all LEDs off when the command terminates without
  error, L2 on if the command terminates with an error

* if the basename of this script contains "fg", the foreground copy of the
  script runs "tail -f" on the output file and the background copy will
  kill the "tail" when it exits; this provides an "interruptable" pseudo-
  foreground run

It's no substitute for a real window system, or even for job control, but
even windows aren't perfect for everything; I use this to do compiles a lot,
then inspect the logs for errors (bg) and/or load it into Emacs and let it
parse the error messages.

A quick example of the log file:

	Sun Jul 16 12:05:21 EDT 1989
	$$ mkshar bg
	o - shar
	a - bg
	$$ exit 0
	Sun Jul 16 12:05:33 EDT 1989

Shar(e) and enjoy.
++Brandon

#--------------------------------CUT HERE-------------------------------------
#! /bin/sh
#
# This is a shell archive.  Save this into a file, edit it
# and delete all lines above this comment.  Then give this
# file to sh by executing the command "sh file".  The files
# will be extracted into the current directory owned by
# you with default permissions.
#
# The files contained herein are:
#
# -rwxr-xr-x   1 allbery  member      1294 Jul 16 12:05 bg
#
echo 'x - bg'
if test -f bg; then echo 'shar: not overwriting bg'; else
sed 's/^X//' << '________This_Is_The_END________' > bg
X:
X# fg/bg: run command in background, niced, with output to file
X# notify user upon command completion
X# if invoked as "fg", start "tail -f" on log file in foreground, killing
X# it automatically when background finishes
X#
X# remove ## from lines below to get notification on VT100s or close compatibles
X# via LEDs:  L1 on when process running, L2 on if process exited with error,
X# all LEDs off if process exited without error (useful!)
X#
X# this version does not handle user logout (well); I have one which does a
X# slightly better job but is rather buggy, so I'm not releasing it
X#
X# I hereby release this script into the public domain.  ++Brandon
X
Xcase $# in
X0)	echo "usage: $0 command [args ...]" >&2
X	exit 1
X	;;
Xesac
Xname=`basename $0 .sh`
X> ./$name.out
X{
X##	[ "$TERM" = vt100 ] && echo '\033[q\033[1q\c'
X	trap '' 3 2 1
X	date >> ./$name.out
X	echo "\$\$ $@" >> ./$name.out
X	{
X		eval nice -20 "$@"
X	} >> ./$name.out 2>&1
X	status=$?
X	echo "\$\$ exit $status" >> ./$name.out
X	date >> ./$name.out
X##	[ "$TERM" = vt100 ] && echo '\033[q\c'
X	if [ $status -ne 0 ]; then
X		echo '\007\c'
X##		[ "$TERM" = vt100 ] && echo '\033[2q\c'
X		sleep 1
X	fi
X	echo '\007\c'
X	sleep 1
X	echo '\007\c'
X	case "$name" in
X	*fg*)	kill -2 $$ 2> /dev/null ;;
X	esac
X} &
Xcase "$name" in
X*fg*)	exec tail -f ./$name.out ;;
Xesac
________This_Is_The_END________
if test `wc -c < bg` -ne 1294; then
	echo 'shar: bg was damaged during transit (should have been 1294 bytes)'
fi
fi		; : end of overwriting check
exit 0
-- 
Brandon S. Allbery, moderator of comp.sources.misc	     allbery at ncoast.org
uunet!hal.cwru.edu!ncoast!allbery		    ncoast!allbery at hal.cwru.edu
      Send comp.sources.misc submissions to comp-sources-misc@<backbone>
NCoast Public Access UN*X - (216) 781-6201, 300/1200/2400 baud, login: makeuser
* "ncoast" regenerates again!  The 5th "ncoast", coming August 1 (stay tuned) *