Linux Process Monitoring

Use the shell script below to run only one instance of a script, and if the process fail, restart it.

$ vi proc_mon.sh
#!/bin/bash
#set -x
#Usage: proc_mon.sh <Unique Text to Grep> <command to start process>
grepText="${1}"
procStart=$2
logFile=/tmp/$1.log
echo "Text to grep to find process: "${grepText}
echo "Command to Start process    : "${procStart}
echo "Log file location           : ${logFile}"
nProc=`ps -ef|grep ${grepText}|grep -v grep|grep -v proc_mon.sh|awk '{print $2}'|wc -l`
echo ${nProc}
case ${nProc}  in
0)  echo "Starting :     $(date)" >> ${logFile}
    ${procStart} &
    ;;
1)  # all ok
    ;;
*)  echo "Removed double proc: $(date)" >> ${logFile}
    kill `ps -ef|grep ${grepText}|grep -v grep|grep -v proc_mon.sh|awk '{print $2}'|head -n 1`
    ;;
esac

Create below cron job to run the monitoring script every minute:

crontab -e
* * * * * /<path to proc_mon>/proc_mon.sh start.js /<path to command>/<command>.sh > /tmp/proc_monitor.log 2>&1