cron(8) is a daemon that runs a command or script on a regular schedule as a specified user. Typically, the user who wishes to schedule a task manually creates a crontab(5) using syntax that can be perplexing to new Unix users. The FreeNAS® GUI makes it easy to schedule when you would like the task to occur.
NOTE: due to a limitation in FreeBSD, users with account names that contain spaces or exceed 17 characters are unable to create cron jobs.
Figure 4.1a shows the screen that opens when you click System → Cron Jobs → Add Cron Job:
Figure 4.1a: Creating a Cron Job
Table 4.1a summarizes the configurable options when creating a cron job.
Table 4.1a: Cron Job Options
|User||drop-down menu||make sure the selected user has permission to run the specified command or script|
|Command||string||the full path to the command or script to be run; if it is a script, test it at the command line first to make sure that it works as expected|
|Minute||slider or minute selections||if use the slider, cron job occurs every N minutes; if use minute selections, cron job occurs at the highlighted minutes|
|Hour||slider or hour selections||if use the slider, cron job occurs every N hours; if use hour selections, cron job occurs at the highlighted hours|
|Day of month||slider or month selections||if use the slider, cron job occurs every N days; if use day selections, cron job occurs on the highlighted days|
|Month||checkboxes||cron job occurs on the selected months|
|Day of week||checkboxes||cron job occurs on the selected days|
|Redirect Stdout||checkbox||disables emailing standard output to the root user account|
|Redirect Stderr||checkbox||disables emailing errors to the root user account|
|Enabled||checkbox||uncheck to disable the cron job without deleting it|