Understanding Cron
Everything you need to know about time-based scheduling in Unix systems. Simple, powerful, and precise.
*
The Wildcard
The asterisk means "every". If used in the Minute field, it triggers every minute.
/
The Step
The slash defines increments. */15 in minutes means "every 15 minutes" (0, 15, 30, 45).
Fields Reference
| Field | Required | Allowed Values | Allowed Special Characters |
|---|---|---|---|
| Minute | Yes | 0-59 | , - * / |
| Hour | Yes | 0-23 | , - * / |
| Day of Month | Yes | 1-31 | , - * / ? L W |
| Month | Yes | 1-12 or JAN-DEC | , - * / |
| Day of Week | Yes | 0-6 or SUN-SAT | , - * / ? L # |