[MLUG] Process ID recycling

[Steeve McCauley]

I always save the pid in /var/run/pname.pid and then do something
like,

pid=$(cat /var/run/pname.pid)
cmd=$(ps -p $pid --no-headers -o %c)
if [ $cmd != pname ]; then
	# no longer running
	exit 0
fi

# still running
kill $pid
# make sure it's terminated
...

To save the pid in the first place, you can use $! to grok the
last process pid run in the background, or use ps like,

nohup pname > /tmp/out 2>&1 &
pid=$!

or

pid=$(ps -C pname --no-headers -o %p)

David Filion wrote:
> Anyone know what the turnaround time or rule is on a process id being 
> reused? 
> 
> I'm looking for ways to kill a process after a fixed amount of time.  
> None of the scripts I've seen so far check that the process ID they 
> saved after the fork/exec actually belongs to the process they launched.
> 
> 
> David
> 
> 
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-- 
Steeve McCauley
Director of Research and Development
Rackable Systems
407 McGill Street, Suite 1002
Montreal, Quebec, H2Y 2G3 (Canada)
Tel: 514-288-3343
http://www.rackable.com
:wq