How a cron expression is structured
A standard cron line has five fields, separated by spaces: minute hour day-of-month month day-of-week. Each field is a number, * (every value), a range like 1-5, a list like 1,15,30, or a step like */15 (every 15th). Read left to right, 30 2 * * 1-5 is "at 02:30, on every weekday."
The gotcha that bites everyone
When you restrict both day-of-month and day-of-week, cron uses an OR, not an AND. 0 0 13 * 5 doesn't mean "Friday the 13th" — it means midnight on the 13th of every month and every Friday. If you want "the 13th only when it's a Friday," cron can't express it directly; you gate it in the job itself.
Cron fires the job. What governs what the job does?
A schedule is easy; a scheduled job that migrates a database or restarts a service unsupervised is where things go wrong. Infraveil is a control plane you run on your own servers — scheduled and ad-hoc production-changing actions alike pass through an approval gate, run with least-privilege access, and land in a tamper-evident audit trail with one-click rollback.
See the live demo →Frequently asked questions
What do the five fields mean?
Minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), day-of-week (0-6, 0/7 = Sunday). Plus *, ranges, lists, and */n steps.
What does */15 * * * * mean?
Every 15 minutes — at minute 0, 15, 30, 45 of every hour.
Both day-of-month and day-of-week set — what happens?
Standard cron runs when either matches (OR), not both (AND). A frequent surprise.