On the Developer Tutorials blog, Akash Mehta has posted an introduction to working with command-line PHP scripts and cron jobs for site automation.

Scheduled tasks are a fairly common feature in modern web applications. From cleaning out caches every 24 hours to checking subscription periods and even generating reports, more web applications live by the clock than ever before. But how do we schedule the execution of a PHP script on the server side?

He shows the two key things to getting it working - an example of a command-line call to a PHP script (executed through his /usr/bin/php) and an example of a line from a crontab showing how to execute the script at midnight every day.

On the PhPL33t blog, there's a guide for automating the creation of email addresses with the Plesk administration application:

In 2003 I wrote "Plesk Auto Email", the first fully funtional Plesk email automation suite. Now, I am going to show you how to do it. You will need a dedicated server with Linux, Plesk 7.5 and higher, php5, mysql5, and root access. This will show you how to code the auto creation, I am not going into deletions and edits at this time because I don't have all night to blog.

Included are the database table to store the commands in, the PHP script to create the commands (the integration into the other piece of software) and the PHP cron script that looks in the command table and executes each as it goes through.