How To Setup a Cron Job on cPanel
You can use cPanel's Cron Job feature to run Unix commands and/or automate the execution of your PHP, Perl, or Python Scripts. You can also specify an email address that the Cron daemon will send the job's results to.
How to get to the Cron Job Page in cPanel
Follow these instructions to navigate to the Cron job page in cPanel:
- Login to cPanel. (yourdonain/cpanel)
Scroll down until you find the Advanced section.
Click on Cron jobs. This will bring you to the Cron Jobs page.
Setting up the Email Notification
Your cron job can notify you through email everytime it runs. Simply type in the email address you wish to use in the field labeled Email, then click on the Update Email button. If you don't want the notification, then you would need to redirect the command's outpupt like this:
mycommand >/dev/null 2>&1
The "mycommand" would be replaced by your command.
Set up a New Cron job
Specify when the cron job will run. The order is:
[minute] [hour] [day] [month] [weekday] [command]
41 04 * * * /my/script -v
This will run every morning at 4:41AM. The * is a wild card, meaning "every day/month, etc" For example; 41 04 * * * = every 41 minutes of every 4th hour of every day of every weekday of month. Weekday is every day of the week including the weekends. Many customers have thought that weekdays are only Monday - Friday, instead of interpreting it as Monday - Sunday.
When setting the time, it is also good to set the cron to run at an odd minute, instead of the top (example: 12:00) or bottom (example: 12:30) of the hour. The example above runs at 4:41. The reasoning behind this is that most people set their crons to run at either the top or bottom of the hour. If everyone runs their crons at the same time, this can cause the crons to run slow and even slow the overall server down for regular website traffic. Setting it at an odd time ensures better performance of the script.
Specify the command to run
The command will have two parts:
[program to execute (perl/pyth./php)] [switches] [script]
The program to run will specify the type of script you are running and will either be:
- php
- Python
The script will need to be called on its direct path as it is located on our server, so it will be something similar to: /home/userna5/public_html/path/to/script, with "userna5" being your username.
perl/cgi scripts should be in your cgi-bin, with permissions of 755.
- To run a PHP script: php -q /home/usern5/public_html/scripts/testrun.php
- For Python scripts: python /home/usern5/public_html/path/to/script
- For Perl/CGI scripts: /home/usern5/public_html/cgi-bin/yourscript.pl
Using the User Agent String
The wget command is disabled on all the shared servers for security purposes. Most scripts that are run via wget can be used with the lynx or curl command. The new mod_security rules that were applied with the latest php updates will prevent lynx and curl from working if a user agent is not set. To set the user agent, you can use the following command:
- curl --user-agent YOUR_STRING (URL)
- lynx -dump -useragent=YOUR_STRING (URL)
Your full cron job command would end up looking like this:
/usr/bin/curl --user-agent cPanel-Cron http://example.com/cron.php
In this case we defined our curl User-Agent to be cPanel-Cron, you can set it to be whatever you'd like, so long as it is defined in your cron command as something.
