The software utility cron is a time-based job scheduler in Unix-like computer operating systems. You can setup and maintain your scripts that executes a command on any given interval to schedule jobs (commands or shell scripts) to run periodically at fixed times, dates, or intervals. It typically automates system maintenance or administration—though it’s general-purpose nature you can use it for cleaning your database or clean files from your temp directory at regular intervals.
For example, scripts like Drupal, Joomla may require you to setup a cron job to perform clean-up of temp folders and certain functions.
Cron Job Time Intervals.
Cron jobs are very resourceful tools as they can be set to run by the minute, hour, day of the week and month or any of the combinations. ibOomz have some limitations to the shared hosting plans to set cron jobs, all our shared hosting plan has an increments of no less than every 15mins since excessive cron jobs may cause excessive loads on server.
What you must know before using a cron job.
There are three important components present for setting up a cron job.
Script that’s been called or executed
Commands that executes the script on recurring basis
The output or an action of script
Most of the scripts will inform you on setup, what jobs are need to set on crons.