Learn Cron
Five-field cron specifies minute, hour, day-of-month, month and weekday. Use an explicit timezone.
Read each short explanation, work through the example, then answer a pop quiz. Every answer explains the reasoning. Incorrect answers unlock a fresh question on the same idea; the full lesson contains ten questions.
01Understand the basics
Ready to learnA common five-field cron expression selects minute, hour, day of month, month and day of week, in that order. Cron implementations differ, so confirm the scheduler and timezone. The tools here use numeric five-field expressions in UTC.
02Understand field steps
Ready to learnA step selects matching values within a field. It does not always represent a constant elapsed interval across field boundaries.
Try a different value
03Choose the time basis
Ready to learnUTC avoids daylight-saving clock changes in the schedule. A local-time scheduler may skip or repeat a wall-clock time when clocks change. Monitor execution and define missed-run behaviour.
You’ve practised all three sections.
First-attempt understanding and later practice are shown separately. Keep practising with the related tools or continue through the suggested path.
Put it to work
Apply what you’ve learned using the related tools.