CronDrive

Test a cron expression

See what it means and when it runs next, in your time zone.

It's 16:27 there now (UTC+00:00).

Which time zone do I choose?

The time zone of the server where the crontab runs, which may not be yours. To see it, run this on the server:

timedatectl | grep "Time zone"

If the crontab sets CRON_TZ, choose that one.

Format

Cron is driven by a crontab (cron table) file, a configuration file that specifies shell commands to run periodically on a given schedule. On Linux you can run crontab -e to edit it.

Each line has a cron expression made of five fields, followed by a shell command to execute. A * means every value; 1,5 is a list, 1-5 a range and */5 a step.

* minute 0-59
* hour 0-23
* day 1-31
* month 1-12
* weekday 0-6, Sunday is 0

Examples

Expression Description
* * * * * Every minute
*/2 * * * * Every 2 minutes
*/3 * * * * Every 3 minutes
*/5 * * * * Every 5 minutes
*/10 * * * * Every 10 minutes
*/15 * * * * Every 15 minutes
*/20 * * * * Every 20 minutes
*/30 * * * * Every 30 minutes
0 * * * * Every hour
0 * * * 1-5 Every hour on Monday through Friday
0 */2 * * * Every 2 hours
0 */3 * * * Every 3 hours
0 */4 * * * Every 4 hours
0 */6 * * * Every 6 hours
0 */8 * * * Every 8 hours
0 */12 * * * Every 12 hours
0 0 * * * Every day at 00:00
0 2 * * * Every day at 02:00
0 8 * * 1-5 At 08:00 on Monday through Friday
0 0 * * 1 At 00:00 on Monday
0 0 * * 0 At 00:00 on Sunday
0 0 */5 * * At 00:00 every 5 days
0 0 1 * * At 00:00 on day 1 of the month
1,5 * * * * At minutes 1 and 5 of every hour
1-5 * * * * At minutes 1 through 5 of every hour
0 1 * * 1,2 At 01:00 on Monday and Tuesday
30 9-17 * * 1-5 Every hour from 09:30 to 17:30 on Monday through Friday