#!/bin/sh

if [ -f /var/tmp/.crontab.bak ]
then
    old="$(md5sum /var/tmp/.crontab.bak | cut -d ' ' -f 1)"
    current="$(md5sum /etc/crontab | cut -d ' ' -f 1)"

    if [ "$old" = "$current" ]
    then
        exit 0
    else
        echo "/etc/crontab has been modified." | mail root
        cat /etc/crontab > /var/tmp/.crontab.bak
    fi
else
    echo "No old file. Creating a new one."
    cat /etc/crontab > /var/tmp/.crontab.bak
fi