Shell script for process monitoring

Shell Programming and Scripting
1

Im having a bit of troble coming up with a script that does this monitors processes to see if they die, if they do die, restart the process
and write out to a log file that the process was restarted with the new PID and the date and time the new process was launched.

Any suggestions?

2

Which OS are you using?

Assuming you want to monitor a process named atd and pidof is available:

#!/bin/bash

_prg=atd
_logfile=monitor.log

while sleep 60; do                                        # poll every minute ...
  pgrep -f "$_prg" >/dev/null || {                        # if process not available
    start atd  >/dev/null 2>&1                            # start it and log the operation
    printf '[%s] %s started with pid %d at %s\n' \
      "$( date )" "$_prg" $( pgrep -f "$_prg" ) >> "$_logfile"
      }
done

If pgrep is not available, you may try some of these:

ps -C <your_program> -o pid=

The last option could be something like this (assuming your process is atd):

ps -eo pid,args= | grep '[a]td' |cut -d\  -f2

Bare in mind, that if you're starting your process in background, its pid will be available in the $! variable (so you won't need all the stuff above).