🚀 go-pugleaf

root@fns.gold.sub.org (Peter Bechtold) writes:
> jkscott@EOS.NCSU.EDU (JENNIFER KAYE SCOTT) writes:
>>I need to program a shell script that can check to see if a certain process
>>is running, and if it noe, then start up the process.

>Try this :

>#!/bin/sh
>if test -z "`ps -e|grep PROCESSNAME`"
>then
>	exec PROCESSNAME
>else
>	echo "PROCESSNAME is running"
>fi

Slight flaw here:

	$ sleep 10 &
	16151
	$ ps | grep sleep
	16151 q0 S     0:00 sleep 10
	16152 q0 S     0:00 grep sleep
	$

You need to run the output of the first grep thru "grep -v grep".
Also, if your grep returns a status, you can just say

	if ps | grep $PROCESSNAME | grep -v grep >/dev/null; then
		...

Unfortunately, this _still_ isn't reliable.  Even if the target
process isn't running, the string you're searching for may be present
as part of the command line of another process.

Here's a better solution.  Given the following output from ps

	  PID TT STAT  TIME COMMAND
	14807 p5 IW    0:00 -sh (csh)
	15881 p5 IW    0:02 nn
		...

where the command starts in column 5, do

	if ps | awk "\$5 ~ /^-?(.*\/)?$PROCESSNAME\$/ { S=0; }
		     END { exit(S); }" S=1 -; then
		echo foo
	fi

which will, for example, find "sh" if it appears as "sh, "-sh", or
"/bin/sh", but not as "rsh" or (say) "emacs showme.txt".


chris ross   <cjross@bbn.com>   BBN Advanced Simulations   (617) 873-3272
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