PatternCron
Every hour, on the hour
The simplest recurring schedule after "every minute": minute 0 of every hour — and why the leading 0 is the whole expression.
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In plain English
- Fires at minute 0 of every hour
- 24 runs per day
Why it’s written this way
Only the minute field is constrained: at minute 0 of any hour, any day, the job fires. Fixing one field and starring the rest is the basic grammar every other schedule builds on.
The rookie version — * * * * * with "hourly" in mind — actually runs every MINUTE. If the minute field is a star, the job fires 60 times an hour.
Edge cases to know
- →Every job on the machine that chose :00 fires together; picking an offset minute (7 * * * *) spreads the load for free.
- →If the job can run longer than an hour, add a lockfile guard — cron happily starts the next run alongside the last.