Cron and Blog

Cron script - is typically a unix shell script that's scheduled to run at preset times. Similar to Scheduled Tasks in Windows, but far more powerful. It is handled by Cron which is a clock daemon.
Much more info: http://www.google.com/search?&q=cron

Blog - abbreviation for weblog. It is usually just a simple web site maintained by one or more persons who post messages frequently describing recent events that they find significant. This might be stuff that happens in their daily lives, or perhaps new developments in some technology circle, or both, and anything else. Many are boring, some are entertaining, and few are really informative.
More info: http://www.google.com/search?&q=blog

more about cron...

suppose you have a php script on your website that you want to be executed every 5 minutes. you use cron for that. you create a cron entry where you define how often the script will be executed and what script it is (i.e. the command the runs the script like "php myscript.php"). cron is the most widely used program to do this. it comes packaged with Linux and serves its purpose very well. it is very simple too.