Sometimes you don’t want to get any notifications from your cronjob, but somewhere in the code someone echos something and so you get an email each time. That could be very annoying. The following snipped will help you to immobilize the cron.
*/5 * * * * /var/wwww/whatever.php > /dev/null 2>&1
The important part is > /dev/null 2>&1. This throws every output into a black hole.