Cron Expression Examples and Schedule Debugging
Use this page when a schedule looks plausible on paper but you still need to verify how a standard 5-field cron expression will behave in practice.
Keep this scoped to the current ComUtil cron parser: it previews standard 5-field cron schedules with shareable examples and explicit validation, not Quartz seconds fields or production scheduler control.
Use this when
A schedule is running too often, not often enough, or at the wrong day/hour and you need a clear explanation before editing production config.
What to inspect first
Check the normalized expression, preview timezone, and next-run timeline together before you assume the scheduler is wrong.
Guardrail
This guide stays on standard 5-field cron. If the source expression includes seconds or year fields, trim it before you preview it here.
Business-hours polling
Use a weekday hourly example when you need to explain office-hours automation to another reviewer.
0 9-17 * * 1-5
Every 5 minutes
Check a regular polling cadence before you treat a high-frequency job as a deployment or queue problem.
*/5 * * * *
Nightly backup
Preview a backup window with exact next-run timestamps before you widen the debugging scope.
30 2 * * *
This workflow is for standard 5-field cron schedules, so it is a good fit for common Linux cron, many CI jobs, and other minute-level schedulers.
- Remove seconds or year fields before you paste a Quartz-style expression here.
- Treat the timeline as a debugging aid, not as proof that a remote scheduler is configured the same way.
Use the field-by-field breakdown and next-run timeline together when you need to show why a schedule expands the way it does.
- Compare preview timezone and UTC so timezone confusion is visible early.
- Watch the day-of-month and day-of-week interaction when both are restricted.