A cron job is tied to a specific plugin event. Plugins will generally be named after the component whose data said plugin processes. For example, "plg_cron_support" will process or manipulate various content found in the support component (com_support).
Each plugin event may specify parameters or settings that can be specified for the chosen event. Parameters are stored on a per-job basis, allowing you to have multiple jobs that utilize the same event but are passed different parameters. For example, one could have a cron job that sends out an email reminder once a week for support tickets that are marked "high prioerity" and another job that sends out a reminder once a month for tickets marked as "normal priority".
Event parameters are generally optional and some events may not even have parameters associated with them.
Several common recurrences are specified for ease of use but, if desired, one can specify a custom recurrence by choosing "Custom" from the select list.
# * * * * * # ┬ ┬ ┬ ┬ ┬ # │ │ │ │ │ # │ │ │ │ │ # │ │ │ │ └───── day of week (0 - 7) (0 to 6 are Sunday to Saturday; 7 is Sunday, the same as 0) # │ │ │ └────────── month (1 - 12) # │ │ └─────────────── day of month (1 - 31) # │ └──────────────────── hour (0 - 23) # └───────────────────────── min (0 - 59)
The following options control various aspects of the published state (when and if a job should be run).