[php] How to run a cronjob every X minutes?

# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed

To set for x minutes we need to set x minutes in the 1st argument and then the path of your script

For 15 mins

*/15 * * * *  /usr/bin/php /mydomain.in/cromail.php > /dev/null 2>&1