Prevent process from killing itself using pkill

Question

I'm writing a stop routine for a start-up service script:

do_stop()
{
  rm -f $PIDFILE
  pkill -f $DAEMON || return 1
  return 0
}

The problem is that pkill (same with killall) also matches the process representing the script itself and it basically terminates itself. How to fix that?

Answer 1

You can explicitly filter out the current PID from the results:

kill $(pgrep -f $DAEMON | grep -v ^$$\$)

To correctly use the -f flag, be sure to supply the whole path to the daemon rather than just a substring. That will prevent you from killing the script (and eliminate the need for the above grep) and also from killing all other system processes that happen to share the daemon's name.

Answer 2

pkill -f accepts a full blown regex. So rather than pkill -f $DAEMON you should use:

pkill -f "^"$DAEMON

To make sure only if process name starts with the given daemon name then only it is killed.

A better solution will be to save pid (Proces Id) of the process in a file when you start the process. And for the stopping the process just read the file to get the process id to be stopped/killed.