UptimePad

Cron examples: common crontab schedules, ready to copy

Each cron example below is a line you can paste into a crontab, with how cron reads it. Open any of them in the generator to see its next run times in your time zone and the matching lines for GitHub Actions and Kubernetes.

By Rai Ansar. Updated .

Every few minutes

A step in the minute field runs the job on every multiple of the step, counted from minute 0 of each hour.

Every few minutes: cron expressions and how cron reads them
ScheduleExpressionHow cron reads itOpen in the generator
Every minute* * * * *Every minute.Open * * * * * in the generator
Every 2 minutes*/2 * * * *Every 2 minutes.Open */2 * * * * in the generator
Every 5 minutes*/5 * * * *Every 5 minutes.Open */5 * * * * in the generator
Every 10 minutes*/10 * * * *Every 10 minutes.Open */10 * * * * in the generator
Every 15 minutes*/15 * * * *Every 15 minutes.Open */15 * * * * in the generator
Every 20 minutes*/20 * * * *Every 20 minutes.Open */20 * * * * in the generator
Every 30 minutes*/30 * * * *Every 30 minutes.Open */30 * * * * in the generator
Every 5 minutes, starting at minute 22-59/5 * * * *Every 5th minute from 2 through 59 of every hour.Open 2-59/5 * * * * in the generator
Every 45 minutes (does not work)*/45 * * * *Every 45th minute. */45 restarts at 0 every hour, so the gap between :45 and :00 is 15 minutes, not 45.Open */45 * * * * in the generator

Steps that do not divide 60 restart at the top of each hour, so */45 runs at :00 and :45, 15 minutes apart. To shift a job off the busy top of the hour, give the step a starting minute, as in 2-59/5. GitHub Actions will not run a schedule more often than every 5 minutes.

Hourly and every few hours

Set the minute to a fixed number, or the job runs every minute of the matching hours.

Hourly and every few hours: cron expressions and how cron reads them
ScheduleExpressionHow cron reads itOpen in the generator
Every hour0 * * * *Every hour at minute 0.Open 0 * * * * in the generator
Every hour at half past30 * * * *Every hour at minute 30.Open 30 * * * * in the generator
Every 2 hours0 */2 * * *At minute 0 past every 2nd hour.Open 0 */2 * * * in the generator
Every 3 hours0 */3 * * *At minute 0 past every 3rd hour.Open 0 */3 * * * in the generator
Every 4 hours0 */4 * * *At minute 0 past every 4th hour.Open 0 */4 * * * in the generator
Every 6 hours0 */6 * * *At minute 0 past every 6th hour.Open 0 */6 * * * in the generator
Every 12 hours0 */12 * * *At minute 0 past every 12th hour.Open 0 */12 * * * in the generator
Every 5 hours (does not work)0 */5 * * *At minute 0 past every 5th hour. */5 restarts at 0 every day, so the gap between 20:00 and 00:00 is 4 hours, not 5.Open 0 */5 * * * in the generator

The hour step restarts at midnight in the same way: */5 runs at 00:00, 05:00, 10:00, 15:00 and 20:00, then again at 00:00 after a gap of 4 hours. Writing * in the minute field by mistake, as in * */2 * * *, runs the job 60 times in each matching hour.

Daily

Hours use the 24-hour clock in the time zone of the machine or service that runs the job.

Daily: cron expressions and how cron reads them
ScheduleExpressionHow cron reads itOpen in the generator
Every day at midnight0 0 * * *At 00:00 every day.Open 0 0 * * * in the generator
Every day at 02:3030 2 * * *At 02:30 every day.Open 30 2 * * * in the generator
Every day at 06:000 6 * * *At 06:00 every day.Open 0 6 * * * in the generator
Every day at noon0 12 * * *At 12:00 every day.Open 0 12 * * * in the generator
Twice a day, at midnight and noon0 0,12 * * *At 00:00 and 12:00 every day.Open 0 0,12 * * * in the generator
Every hour from 01:00 to 05:000 1-5 * * *At minute 0 past every hour from 1 through 5.Open 0 1-5 * * * in the generator

Where clocks change for daylight saving, the hour they jump over is skipped in spring and the hour they go back over happens twice in autumn. cronie runs a fixed-time job from a skipped hour straight after the change and runs it only once in a repeated hour. The generator flags those runs for any time zone, and a schedule kept in UTC has neither problem.

Weekdays and weekly

In the day-of-week field 0 and 7 are both Sunday, and 1-5 is Monday to Friday.

Weekdays and weekly: cron expressions and how cron reads them
ScheduleExpressionHow cron reads itOpen in the generator
Every weekday at 09:000 9 * * 1-5At 09:00 on Monday through Friday.Open 0 9 * * 1-5 in the generator
Every Saturday and Sunday at 10:000 10 * * 0,6At 10:00 on Sunday and Saturday.Open 0 10 * * 0,6 in the generator
Every Monday at 09:000 9 * * 1At 09:00 on Monday.Open 0 9 * * 1 in the generator
Every Friday at 17:000 17 * * 5At 17:00 on Friday.Open 0 17 * * 5 in the generator
Every Sunday at midnight0 0 * * 0At 00:00 on Sunday.Open 0 0 * * 0 in the generator
Every hour in office hours0 9-17 * * 1-5At minute 0 past every hour from 9 through 17 on Monday through Friday.Open 0 9-17 * * 1-5 in the generator
Every 15 minutes in office hours*/15 9-17 * * 1-5Every 15 minutes past every hour from 9 through 17 on Monday through Friday.Open */15 9-17 * * 1-5 in the generator

The office-hours lines include the whole of the last hour, so */15 9-17 runs for the last time at 17:45. Use 9-16 to stop at 16:45.

Monthly, quarterly and yearly

Day 1 and month 1 are the first, so 0 0 1 1 * is midnight on 1 January.

Monthly, quarterly and yearly: cron expressions and how cron reads them
ScheduleExpressionHow cron reads itOpen in the generator
The 1st of every month at midnight0 0 1 * *At 00:00 on day 1 of the month.Open 0 0 1 * * in the generator
The 15th of every month at 09:000 9 15 * *At 09:00 on day 15 of the month.Open 0 9 15 * * in the generator
The 1st and 15th of every month0 0 1,15 * *At 00:00 on days 1 and 15 of the month.Open 0 0 1,15 * * in the generator
Every quarter, on 1 January, April, July and October0 0 1 */3 *At 00:00 on day 1 of the month in January, April, July and October.Open 0 0 1 */3 * in the generator
Every other day (odd dates)0 0 */2 * *At 00:00 on every 2nd day of the month.Open 0 0 */2 * * in the generator
Once a year, at midnight on 1 January0 0 1 1 *At 00:00 on day 1 of the month in January.Open 0 0 1 1 * in the generator

A day-of-month step restarts each month, so */2 runs on the 31st and again on the 1st, one day apart. A job set for the 31st runs only in months that have one. A job for the 30th never runs in February, and one for the 29th runs there only in leap years.

The @ shortcuts

cronie accepts these names in place of the five fields. The Kubernetes CronJob docs list all of them except @reboot, and GitHub Actions accepts none of them.

Cron @ shortcuts and the expressions they stand for
ShortcutSame asHow cron reads it
@hourly0 * * * *Every hour at minute 0.
@daily0 0 * * *At 00:00 every day.
@midnight0 0 * * *At 00:00 every day.
@weekly0 0 * * 0At 00:00 on Sunday.
@monthly0 0 1 * *At 00:00 on day 1 of the month.
@yearly0 0 1 1 *At 00:00 on day 1 of the month in January.
@annually0 0 1 1 *At 00:00 on day 1 of the month in January.
@rebootno fixed timeOnce, after the machine starts.

Schedules cron cannot write in one line

Five fields cover most schedules but not all of them. These are the usual fixes. Each line is a full crontab entry; replace /path/to/job with your command.

Every 30 seconds

* * * * * /path/to/job
* * * * * sleep 30; /path/to/job

Cron counts in whole minutes. Two lines do it: one runs at the start of each minute and the other waits 30 seconds first.

Every 90 minutes

0 0-21/3 * * * /path/to/job
30 1-22/3 * * * /path/to/job

The minute field only goes up to 59, so a step of 90 cannot work. The first line runs at 00:00, 03:00 and so on to 21:00, the second at 01:30, 04:30 and so on to 22:30, which gives a run every 90 minutes all day, 22:30 to 00:00 included.

The last day of the month

0 0 28-31 * * [ "$(date -d tomorrow +\%d)" = 01 ] && /path/to/job

Run on days 28 to 31 and let the command check that tomorrow is the 1st. date -d tomorrow is a GNU date feature, so test it where GNU coreutils is not installed. The backslash stops cron from reading % as a new line.

The first Monday of the month

0 9 1-7 * * [ "$(date +\%u)" = 1 ] && /path/to/job

Putting 1-7 in the day of month and 1 in the day of week does not work, because cron runs on days that match either field. Run on days 1 to 7 and test the weekday in the command instead.

Every other week

0 9 * * 1 [ $(( 1$(date +\%V) \% 2 )) -eq 0 ] && /path/to/job

Run every Monday and let the command skip odd ISO week numbers. The 1 in front turns week 08 into 108, because the shell reads a number with a leading 0 as octal and 08 is not a valid one. Years with 53 weeks put two odd weeks in a row at the turn of the year, so check that January if the gap matters.

Sources

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