[SOLVED] Order of PIDs in kill command

clstanton · 12-12-2014, 11:32 AM

The question comes up yesterday and I have Googled unsuccessfully. In what order does the kill command use when executing multiple PIDs?

rknichols · 12-12-2014, 02:57 PM

I've never seen evidence of any order other than the ordering of the arguments on the command line. But note two things:

Unless you explicitly execute /bin/kill, you are probably getting your shell's built in kill command, so the result is dependent on your shell.
kill just sends a signal to each process. That signal will not be handled until that process is next scheduled for execution, and you have little control over what that sequence might be.

clstanton · 12-12-2014, 03:49 PM

Thanks. That makes sense. So entry order really would not have control over the termination.
We were told to kill two processes at one time and we were wondering would the order make a difference as the were related.

Thanks again

rknichols · 12-12-2014, 06:37 PM

It's especially true when you consider what each process might need to do to "terminate". The first process that gets the signal might have multiple I/O buffers to flush, and thus terminate some time after a second process that had less cleanup to do.