# Cron Format

The Cron format is a simple yet powerful and flexible way to define the time and frequency of various actions. It consists of five fields, each specifying a different time unit.

The following graph explains it in detail:

```
* * * * * 
| | | | | 
| | | | |
| | | | +---- Day of the Week   (range: 1-7, 1 standing for Monday)
| | | +------ Month of the Year (range: 1-12)
| | +-------- Day of the Month  (range: 1-31)
| +---------- Hour              (range: 0-23)
+------------ Minute            (range: 0-59)
```

Any of these 5 fields may be an asterisk `*`. This would mean the entire range of possible values, i.e. each minute, each hour, etc.

Any field may contain a list of values separated by commas, (e.g. `1,3,7`) or a range of values (two integers separated by a hyphen, e.g. `1-5`).

After an asterisk `*` or a range of values, you can use character `/` to specify that values are repeated over and over with a certain interval between them. For example, you can write `0-23/2` in Hour field to specify that some action should be performed every two hours (it will have the same effect as `0,2,4,6,8,10,12,14,16,18,20,22`); value `*/4` in Minute field means that the action should be performed every 4 minutes, `1-30/3` means the same as `1,4,7,10,13,16,19,22,25,28`.