# Cron

An overview of using Ubuntu's built in Cron system.
```
[minute] [hour] [day_of_month] [month] [day_of_week] [user] [command_to_run]
* * * * * root /root/update.sh
```

| Field | Values allowed |
| --- | --- |
| Minute | 0 to 59 |
| Hour | 0 to 23 |
| Day of month | 1 to 31 |
| Month | 1 to 12 OR JAN to DEC |
| Day of week | 0 to 6 OR SUN to SAT |

| Special Syntax | Regular equivalent |
| --- | --- |
| @hourly | 0 * * * * |
| @daily | 0 0 * * * |
| @weekly | 0 0 * * 0 |
| @monthly | 0 0 1 * * |
| @yearly | 0 0 1 1 * |