Cron(chronos is the Greek word for time) jobs are tasks that run on the server at specific time intervals.
Cron jobs are stored in /var/spool/cron/username files. For plothost user, we have:
root@web [/var/spool/cron]# cat plothost
MAILTO="test@demo.plothost.com"
SHELL="/usr/local/cpanel/bin/jailshell"
* * * * * /plothost/public_html/test.php
root@web [/var/spool/cron]#
We can see the user has only one cron job – the file test.php will be executed every minute.
As an alternative, you can use the crontab command to list the cron jobs for a user. The command is: crontab -u username -l . For user plothost, we have:
root@web [/var/spool/cron]# crontab -u plothost -l
MAILTO="test@demo.plothost.com"
SHELL="/usr/local/cpanel/bin/jailshell"
* * * * * /plothost/public_html/test.php
root@web [/var/spool/cron]#
You can find the cron jobs logs in the /var/log/cron file.
To see the entries for a specific user use cat cron | grep username. For example, for the plothost user we have:
root@web [/var/log]# cat cron | grep plothost
May 2 09:07:29 web crontab[8185]: (plothost) LIST (plothost)
May 2 09:08:12 web crontab[8309]: (plothost) LIST (plothost)
May 2 09:08:12 web crontab[8310]: (plothost) REPLACE (plothost)
May 2 09:08:12 web crontab[8313]: (plothost) LIST (plothost)
May 2 09:09:01 web crond[29907]: (plothost) RELOAD (/var/spool/cron/plothost)
May 2 09:09:01 web CROND[8466]: (plothost) CMD (test.php)
May 2 09:10:01 web CROND[8698]: (plothost) CMD (test.php)
May 2 09:11:01 web CROND[8971]: (plothost) CMD (test.php)
root@web [/var/log]#
If for any reason you want to restart the crond service use:
root@web [~]# service crond restart
Redirecting to /bin/systemctl restart crond.service
root@web [~]#
Take care when working with cron jobs. Make a backup before modifying a cron job file.