Script-Check if process running, if not start it up

[Greg Hale]

Can anyone recommend a script that will check to see if a process is running and if it isn't attempt to start it back up?

thanks,

Greg

[Victor BERRIDGE · Accepted solution]

Hi,
I would write a script to be run by cron like:

#script
PROC=`ps -ef? grep -c ?your_proc?`

case $PROC in
1) #Process OK
;;
0) # Not there so start it
/sbin/init.d/ Sxxxesac
#exit

Good luck
All the best
Victor

[Sandor Horvath_2]

Hi !

Use ps -e instead of ps -ef and
grep ' proc_name$'.

So
if [ $(ps -e | grep ' proc_name$' | wc -l) -ne 0 ]
then
exit # process run
fi

regards, Saa

[James R. Ferguson]

Hi Greg:

Here's a hypothetical script that monitors a process that it spawns, restarting the process as soon as it dies. It gives you another example to think about:

#!/usr/bin/sh
function WHAT
{
sleep 30 & #...run in background...
}
while true #...forever...
do
WHAT
WHO=$!
echo "pid_${WHO} started"
while true
do
kill -0 $WHO 2> /dev/null #...check for the pid...
if [ $? -ne 0 ]
then
echo "\npid_${WHO} died"
break #...exit inner loop ...
else #...it's still alive...
sleep 1
echo ".\c"
fi
done
done
#_end

...JRF...

[Alan Riggs]

There are lots of ways to solve this problem. One of them is to use the init process. Anything started from inittab with a "respawn" flag is started at the specified run level, monitored, and restarted if it dies.

Why reinvent the wheel?

[Steven Sim Kok Leong]

Hi,

If you are involving the use of grep on a ps output, please remember to add a "| grep -v grep".

This is because grep itself is a process displayed with ps. If you ps -fae|grep PROC_NAME, other than the PROC_NAME process being reflected, "grep PROC_NAME" process will also be reflected. By adding "| grep -v grep" to form a "ps -fae|grep PROC_NAME|grep -v grep", you effectively filter off the display of the grep process.

Hope this helps. Regards.

Steven Sim Kok Leong
Brainbench MVP for Unix Admin
http://www.brainbench.com