Run cron job only if it isn't already running

Question

I\'m trying to set up a cron job as a sort of watchdog for a daemon that I\'ve created. If the daemon errors out and fails, I want the cron job to periodically restart it...

Answer 1

Consider using pgrep (if available) rather than ps piped through grep if you're going to go that route. Though, personally, I've got a lot of mileage out of scripts of the form

while(1){
  call script_that_must_run
  sleep 5
}

Though this can fail and cron jobs are often the best way for essential stuff. Just another alternative.