RunWisp

Run a cron job every 6 months

0 0 1 */6 * Check it below, then take the line for any of 17 schedulers.

Click to edit · paste a crontab line · hover a field for its values

At 00:00 on day 1 of the month in January and July.

 

Nothing to watch out for on Debian / Ubuntu cron.

crontab line 
# crontab -e  (runs on the server's clock: UTC)
0 0 1 */6 *  /path/to/command
Debian / Ubuntu cron RunWisp Server was off Skipped. anacron only catches up cron.daily, weekly and monthly. Runs the most recent missed run at start-up (catch_up = 1) and sends a missed-run alert.A run fails Output is mailed if MAILTO and a mail server work. No output, no mail, whatever the exit code. Marked failed and sent to your alert channels. retry_attempts adds retries.

· sudo runwisp takeover runs your crontab as it is · How RunWisp compares

Details

Upcoming runs
Calendar 2 days a year
Between two dates
Daylight saving

When things go wrong Server off: Skipped
Server was off
Skipped. anacron only catches up cron.daily, weekly and monthly.
Last run still going
Starts another copy on top.
A run fails
Output is mailed if MAILTO and a mail server work. No output, no mail, whatever the exit code.
Time zone
The server's zone. TZ= in a crontab only reaches the command.
Precision
1 minute.

Sources: manpages.debian.org,manpages.debian.org

Other schedulers As written in 10 of 16
  • ✓ cronie 0 0 1 */6 * vs RunWisp
  • ✓ BusyBox crond 0 0 1 */6 *
  • ↻ systemd timer *-01/6-01 00:00:00 UTC systemd timer uses OnCalendar=, not cron lines. vs RunWisp
  • ✓ RunWisp 0 0 1 */6 *
  • ✓ Kubernetes CronJob 0 0 1 */6 *
  • ≠ Ofelia 0 0 0 1 */6 * Ofelia puts seconds first, so it reads this as: at 01:00 on every 6th day of the month. vs RunWisp
  • ✓ Dagu 0 0 1 */6 * vs RunWisp
  • ✓ PM2 cron_restart 0 0 1 */6 * vs RunWisp
  • ≠ Jobber 0 0 0 1 */6 * Jobber puts seconds first, so it reads this as: at 01:00 on every 6th day of the month. vs RunWisp
  • ✓ GitHub Actions 0 0 1 */6 *
  • ✓ GitLab CI schedule 0 0 1 */6 *
  • ↻ AWS EventBridge Scheduler cron(0 0 1 */6 ? *) AWS EventBridge Scheduler takes cron() with 6 fields, a year last, and ? in one day field.
  • ✓ Google Cloud Scheduler 0 0 1 */6 *
  • ✓ Jenkins 0 0 1 */6 *
  • ↻ Quartz 0 0 0 1 */6 ? Quartz takes 6 or 7 fields, seconds first, with ? in one day field.
  • ↻ Spring @Scheduled 0 0 0 1 */6 * Spring @Scheduled takes exactly 6 fields, seconds first.

✓ works as written · ↻ different syntax · ≠ runs at other times · ? not documented · ✗ can't
Schedulers

Every 6 months, in every scheduler

Works as written in 11 of 17. Times are UTC; the checker above takes any zone.

Runs in 2027
2
Days with a run
2
Longest gap
181 days
SchedulerLineNotes
Debian / Ubuntu cron ✓ 0 0 1 */6 * Works as written.
cronie ✓ 0 0 1 */6 * Works as written.
BusyBox crond ✓ 0 0 1 */6 * Works as written.
systemd timer ↻ OnCalendar=*-01/6-01 00:00:00 UTC systemd timer uses OnCalendar=, not cron lines.
RunWisp ✓ 0 0 1 */6 * Works as written.
Kubernetes CronJob ✓ 0 0 1 */6 * Works as written.
Ofelia ≠ 0 0 0 1 */6 * Ofelia puts seconds first, so it reads this as: at 01:00 on every 6th day of the month.
Dagu ✓ 0 0 1 */6 * Works as written.
PM2 cron_restart ✓ 0 0 1 */6 * Works as written.
Jobber ≠ 0 0 0 1 */6 * Jobber puts seconds first, so it reads this as: at 01:00 on every 6th day of the month.
GitHub Actions ✓ 0 0 1 */6 * Works as written.
GitLab CI schedule ✓ 0 0 1 */6 * Works as written.
AWS EventBridge Scheduler ↻ cron(0 0 1 */6 ? *) AWS EventBridge Scheduler takes cron() with 6 fields, a year last, and ? in one day field.
Google Cloud Scheduler ✓ 0 0 1 */6 * Works as written.
Jenkins ✓ 0 0 1 */6 * Works as written.
Quartz ↻ 0 0 0 1 */6 ? Quartz takes 6 or 7 fields, seconds first, with ? in one day field.
Spring @Scheduled ↻ 0 0 0 1 */6 * Spring @Scheduled takes exactly 6 fields, seconds first.

✓ works as written · ↻ different syntax · ≠ runs at other times · ? not documented · ✗ can't

RunWisp

Cron runs the line. Nobody tells you how it went.

RunWisp is an open-source cron replacement that ships as a single binary. It reads the same cron line and keeps a record of every run: output, exit code, duration.

crontab 
# crontab -e  (runs on the server's clock: UTC)
0 0 1 */6 *  /usr/local/bin/job.sh
runwisp.toml 
[tasks.job]
cron     = "0 0 1 */6 *"
timezone = "UTC"
run      = '/usr/local/bin/job.sh'
cronRunWisp
The server was off at run time Skipped. anacron only catches up cron.daily, weekly and monthly. Runs the most recent missed run at start-up (catch_up = 1) and sends a missed-run alert.
The last run is still going Starts another copy on top. Queues it. on_overlap = "queue" is the default.
A run fails Output is mailed if MAILTO and a mail server work. No output, no mail, whatever the exit code. Marked failed and sent to your alert channels. retry_attempts adds retries.

Keep your crontab. sudo runwisp takeover runs it where it is and retires cron, crontab -e keeps working, and runwisp service uninstall puts cron back. It needs Linux with systemd; elsewhere, runwisp import cron converts the file. RunWisp doesn't do L, W or #, and it runs on one machine, not a cluster. Moving from cron →

FAQ

Questions

What does 0 0 1 */6 * mean?
At 00:00 on day 1 of the month in January and July. In 2027 that's 2 runs on 2 days. Times are in the scheduler's time zone, usually the server's.
How do I run a job every 6 months with a systemd timer?
OnCalendar=*-01/6-01 00:00:00 UTC. systemd timer uses OnCalendar=, not cron lines.
How do I run a job every 6 months in a Kubernetes CronJob?
0 0 1 */6 * works as written.
How do I run a job every 6 months in GitHub Actions?
0 0 1 */6 * works as written.
How do I run a job every 6 months on AWS EventBridge?
cron(0 0 1 */6 ? *). AWS EventBridge Scheduler takes cron() with 6 fields, a year last, and ? in one day field.
More

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curl -fsSL https://get.runwisp.com | sh
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