How to run a cronjob every X minutes?
I'm running a PHP script in a cronjob and I want to send emails every 5 minutes
My current (crontab) cronjob:
10 * * * * /usr/bin/php /mydomain.in/cromail.php > /dev/null 2>&1
The cronmail.php is as follows:
<?php
$from = 'D'; // sender
$subject = 'S';
$message = 'M';
$message = wordwrap($message, 70);
mail("[email protected]", $subject, $message, "From: $from\n");
?>
But I've not received an email in 30 minutes with this configuration.
Answer
In a crontab file, the fields are:
- minute of the hour.
- hour of the day.
- day of the month.
- month of the year.
- day of the week.
So:
10 * * * * blah
means execute blah at 10 minutes past every hour.
If you want every five minutes, use either:
*/5 * * * * blah
meaning every minute but only every fifth one, or:
0,5,10,15,20,25,30,35,40,45,50,55 * * * * blah
for older cron executables that don't understand the */x notation.
If it still seems to be not working after that, change the command to something like:
date >>/tmp/debug_cron_pax.txt
and monitor that file to ensure something's being written every five minutes. If so, there's something wrong with your PHP scripts. If not, there's something wrong with your cron daemon.