Cronjob via PHP (delayed useraction)

[Rasfunk]

Hi everyone!
I am pretty new to linux/apache/mysql/php webdevelopment, and already face some serious problems ;-)

For my current project it is necessary that some useraction is perfomed on the database with a delay (may be only minutes, may be days), even if the user does not stay on the website and disconnects. I already heart that so called "cron jobs" are doing this kind of job, but I wonder how to initiate those cron jobs via PHP, can you help me or give me a short example?

Or is there another, perhaps even better way to implement such a delay (I heart some rumours about CGI...)? Does anyone know a good website where I can find information?

Many thanks in advance,

Timor

[bubblenut]

Right it's not advised to edit the crontab file directly because a syntax error in the crontab will cause it to fail completely thus stopping any other croned scripts. What I would suggest is putting one script in your crontab which is run every five minutes or something like that. Then have this script handle all the events, this way you can store the events in the database and pull them out as and when you need them.
Right adding a php script to the crontab:
First off, you'll want to have a look at how php works from the command line
Then you'll want to learn about how crontab works.
You also need to check you can run php from the command line.
The kind of command you want to betering in your crotab is
1 /usr/bin/php -q /path/to/file.php

HTH
Bubble