Template

 # * * * * *  command to execute
 # │ │ │ │ │
 # │ │ │ │ │
 # │ │ │ │ └───── day of week (0 - 6) (0 to 6 are Sunday to Saturday, or use names; 7 is Sunday, the same as 0)
 # │ │ │ └────────── month (1 - 12)
 # │ │ └─────────────── day of month (1 - 31)
 # │ └──────────────────── hour (0 - 23)
 # └───────────────────────── min (0 - 59)

Running jobs

every first monday of a month

* 12 1-7 * * test $(date '+\%u') -eq 1 && run_job.sh

every second tuesday of a month

* 12 8-14 * * test $(date '+\%u') -eq 2 && run_job.sh

Notes:

  • Cron requries an escaped %-character.