topic Re: Find PID's in Operating System - HP-UX

Find PID's

Vibhor Kumar Agarwal — Tue, 16 Aug 2005 04:08:46 GMT

I have a script which spawns multiple compilations.

Sometimes due to some errors i have to terminate that script.
Now comes the main part, how do I do that?

I can see the individual compilations via
ps -ef | grep compiler
and also kill them via
kill -9 pid

But the scirpt continues:

How do i find out which is the master script which gave birth to all these sub-processes.
This can't be a single step of seeing the PPID in the ps, as its a 3-4 step parent-child process.

Thanks.

Re: Find PID's

Simon Hargrave — Tue, 16 Aug 2005 04:30:08 GMT

Depending how your child processes are called, you can use "ps -g PID". Assuming PID is the process group leader.

For example if I have a shell and run a long find command, then from another shell I do ps -g I get: -

$ ps -g 4068
PID TTY TIME COMMAND
4068 pts/17 0:00 sh
12200 pts/17 0:00 find

If this doesn't work for you, and you have control over the scripts that run your compiles, you could have them all output their PID to a file in /var/run, and then you can kill the entire list if required.

Re: Find PID's

Peter Godron — Tue, 16 Aug 2005 04:37:41 GMT

You have to track back via the PPID of one of the compile processes.
Please remember to cancel the child before the parent!

Re: Find PID's

Vibhor Kumar Agarwal — Tue, 16 Aug 2005 04:41:28 GMT

Thanks Simon and Peter.

But i can't backtrack as the tree goes to 4-5 steps.
Further by the time i start traversing the tree some of the child process completes giving me an illegal PID.

Re: Find PID's

Peter Godron — Tue, 16 Aug 2005 04:50:23 GMT

Dump the output of the ps -ef command to a file to geta frozen status, then use that file to trace the PID and PPID.
Example:

Process x has ppid 1234
find process with pid 1234, which will give you PPID 2345
repeat until PPID is 1

Re: Find PID's

Vibhor Kumar Agarwal — Tue, 16 Aug 2005 04:57:31 GMT

If i have to do this, then i will say let the script do whatever it wants to do and i will start all over again.

Re: Find PID's

Vibhor Kumar Agarwal — Tue, 16 Aug 2005 05:01:27 GMT

Simon,

How do i get the PID of the process group leader.

This is what i am trying to find out.

Re: Find PID's

Simon Hargrave — Tue, 16 Aug 2005 05:08:17 GMT

How you determine this will depend on how you run your script. If it runs from cron you can check the cron log for the PID. Otherwise ps and grep for "compile_script.sh" or whatever is the "master" script, and this will be your group leader.

Re: Find PID's

Vibhor Kumar Agarwal — Tue, 16 Aug 2005 05:13:16 GMT

No,

We simply run it from the command prompt.
I thought of giving the name of script and grep but it won't work as sometimes we don't know the name of script as the running person is a different one.

Don't tell me to ask that person the script name.

Re: Find PID's

Ermin Borovac — Wed, 17 Aug 2005 00:35:47 GMT

Given a process ID (e.g. your compiler) you can find process group ID with

$ UNIX95= ps -p -o pgid=

Then you can find PIDs of all processes assocated with this session with

$ UNIX95= ps -o pid= -g

To put it all together (untested)

$ kill -2 $(UNIX95= ps -o pid= -g $(UNIX95= ps -p -o pgid))