topic Re: while loop not working with remsh in a bourne shell script in Operating System - HP-UX

while loop not working with remsh in a bourne shell script

Boyd Kodama — Thu, 29 Jun 2000 15:44:32 GMT

I wrote a script similar to the following one that root would run to remotely kill the processes owned by user, tester:

#!/usr/bin/sh
remsh 123.45.678.999 ps -ef | grep -v tester | grep -v grep | awk '{print $2}' |
while read pid
do
remsh 123.45.678.999 kill -9 $pid
done
# end of script

Well, it only kills the first process found, i.e. it appears that after it does the first remote kill it exits the while loop although there are other processes listed for $pid.

The "local" version of the script works:
#!/usr/bin/sh
ps -ef | grep -v tester | grep -v grep | awk '{print $2}' |
while read pid
do
kill -9 $pid
done

Any ideas why the `remsh` is causing/allowing the script to loop only once?

thanks

Re: while loop not working with remsh in a bourne shell script

Tim Malnati — Thu, 29 Jun 2000 16:38:34 GMT

The easy workaround to this behavior is to have the actual script reside in an executable file on the remote machine and then inkove it with remsh.

Re: while loop not working with remsh in a bourne shell script

Paul Hite — Thu, 29 Jun 2000 16:41:03 GMT

Your problem is the line:
remsh 123.45.678.999 kill -9 $pid

You need to use:
remsh 123.45.678.999 -n kill -9 $pid

As it now stands, the first time the line is run, it sucks up all the remaining pid lines and sends them to the remote kill process which ignores them.

Re: while loop not working with remsh in a bourne shell script

Albert E. Whale, CISSP — Thu, 29 Jun 2000 16:54:14 GMT

Boyd,

the remsh -n simply redirects stdin from /dev/null.

You'll need to use the following format:

resmh -n -c "kill -9 $pid"

This will work.

Re: while loop not working with remsh in a bourne shell script

Boyd Kodama — Thu, 29 Jun 2000 18:24:54 GMT

Thanks!

Adding the "-n" to the line worked.

A co-worker also suggested the idea of kicking off via remsh a script on the remote systems that would kill the processes. There are 29 that other systems.

Adding the "-c" didn't work. I received a "sh: -c: not found"

Re: while loop not working with remsh in a bourne shell script

Alan Riggs — Thu, 29 Jun 2000 20:25:47 GMT

The -n is the correct solution. The reason it failed is that remsh will by default pull input from stdin. the while loop also relies on stdin. Whenever you use a remsh within a while loop you need to use teh -n flag.

Re: while loop not working with remsh in a bourne shell script

Brian DeHamer — Fri, 30 Jun 2000 00:42:57 GMT