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.