Question

How do you run a cron job every minute only on specific hours? Like so:

It will only check every minute from 11AM to 12AM, 4PM to 5PM and 9PM to 10PM

It seems to be complicated to me I don’t know where to start.

Answer 1

Right solution:

* 11,16,21 * * *

Because if you use previous solution:

0-59 11-12,16-17,21-22 * * * *

Job will start at 12:40 or 17:59. It is not in range from 11AM to 12AM, 4PM to 5PM and 9PM to 10PM.

UPDATE:

Traditional (inherited from Unix) cron format consists of five fields separated by white spaces:

*    *    *    *    *  command to be executed
┬    ┬    ┬    ┬    ┬
│    │    │    │    │
│    │    │    │    │
│    │    │    │    └───── day of week (0 - 6) (0 is Sunday, or use names)
│    │    │    └────────── month (1 - 12)
│    │    └─────────────── day of month (1 - 31)
│    └──────────────────── hour (0 - 23)
└───────────────────────── min (0 - 59)

nnCron can use both traditional and “enhanced” version of cron format, which has an additional (6th) field: Year.