CronDrive

Test a cron expression

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

It's 20:29 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.

At 00:00 every 5 days

0 minute
0 hour
*/5 day
* month
* weekday

Next runs (UTC)

  1. Tue 20 Oct, 00:00
  2. Sun 25 Oct, 00:00
  3. Fri 30 Oct, 00:00
  4. Thu 5 Nov, 00:00
  5. Tue 10 Nov, 00:00
  6. Sun 15 Nov, 00:00
  7. Fri 20 Nov, 00:00
  8. Wed 25 Nov, 00:00
  9. Mon 30 Nov, 00:00
  10. Sat 5 Dec, 00:00

Know when it doesn't run

CronDrive emails you, or posts to Slack, when a job with this schedule fails, or doesn't start or finish on time. Free for up to 15 jobs.

What you'd see with this schedule

An example with the last runs of this schedule and made-up results: one failed and one didn't run.

Times in UTC.

Due
Sat 10 Oct, 00:00 On time Started 00:00, finished 00:13, took 13 min.
Mon 5 Oct, 00:00 Didn't run Alerts sent at 00:05 and 00:30.
Wed 30 Sep, 00:00 On time Started 00:00, finished 00:14, took 14 min.
Fri 25 Sep, 00:00 Failed with code 1 Alert sent at 00:04. Started 00:00, finished 00:04, took 4 min.
Sun 20 Sep, 00:00 On time Started 00:00, finished 00:13, took 13 min.
Tue 15 Sep, 00:00 On time Started 00:00, finished 00:14, took 14 min.

The alert of the failed run

Email from CronDrive, Fri 25 Sep, 00:04

Failed (exit code 1): "Your job"

The job "Your job" failed with exit code 1.

If you connect Slack, the same message goes to your channel.

The change in your crontab

0 0 */5 * * curl -fsS -m 10 https://job.crondrive.com/uG2Exw/start/$$; /path/to/job.sh; curl -fsS -m 10 https://job.crondrive.com/uG2Exw/end/$?/$$

Two calls around your command, in the same line. Your job's line comes with its own token.

Monitor this schedule

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
*/5 * * * * Every 5 minutes
*/10 * * * * Every 10 minutes
*/15 * * * * Every 15 minutes
*/30 * * * * Every 30 minutes
0 * * * * Every hour
0 */2 * * * Every 2 hours
0 */6 * * * Every 6 hours
0 */12 * * * Every 12 hours
0 0 * * * Every day at 00:00
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 1 * * At 00:00 on day 1 of the month
0 */8 * * * Every 8 hours
1,5 * * * * At minutes 1 and 5 of every hour
1-5 * * * * At minutes 1 through 5 of every hour
0 2 * * * Every day at 02:00
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
0 0 */5 * * At 00:00 every 5 days