CRON expression

A CRON expression is a string comprised of 6 or 7 fields separated by white space [ [http://wiki.pentaho.com/display/PentahoDoc/05.+CRON+Expressions+in+Detail 05. CRON Expressions in Detail - Pentaho Wiki ] ] that represents a set of times, normally as a schedule to execute some routine. It is used primarily by the UNIX tool "cron".

Format

{| class="wikitable"
-! Field name! Mandatory?! Allowed values! Allowed special characters
-
Seconds
Yes
0-59
* / , -
-|

pecial Characters

Asterisk (*)

The asterisk indicates that any value for the field is acceptable. For example, using an asterisk in the 5^th field (month) would indicate every month.

Forward slashes (/)

Forward slashes are used to describe increments. For example 0/15 in the 1^st field (seconds) would indicate the 0^th second of the minute and every 15 seconds thereafter.

Commas (,)

Commas are used to separate items of a list. For example, using "MON,WED,FRI" in the 6^th field (day of week) would mean Mondays, Wednesdays and Fridays.

Hyphen (-)

Hyphens denote ranges. For example, 2000-2010 would indicate every year between 2000 and 2010 CE inclusive.

Examples

Every second

* * * * * *

Every minute

0 * * * * *

23:00 every weekday night

0 0 23 ? * MON-FRI

In 2003 CE on the 11th to 16th of each month in January to June every third minute starting from 2 past 1am, 9am and 10pm

0 2/3 1,9,22 11-26 1-6 ? 2003

References