Run a script if a process is not running

runjob_if_not_running.sh

#!/bin/bash -e
#$1 = the regex to identify the job; should use the pattern "[m]y job"
#$2 = the script to run

REGEX=$1
SCRIPT=$2

#try and get the PID
PSID=`ps -ef | grep "$REGEX" -m 01 | awk '{print $2}'`

if [ "$PSID" != "" ] 
then 
  echo 'the job is already running' 
else 
  echo 'the job is not running, starting it using supplied script'
  $SCRIPT
fi