Question 1

What do the 5 fields in a cron expression mean?

Accepted Answer

The five fields are: minute (0–59), hour (0–23), day of month (1–31), month (1–12), and day of week (0–7, where both 0 and 7 mean Sunday). They appear left to right in that order.

Question 2

What does */15 mean in a cron expression?

Accepted Answer

The */n syntax means 'every n values'. So */15 in the minute field means every 15 minutes: at 0, 15, 30, and 45 minutes past the hour.

Question 3

What is the difference between DOM and DOW in cron?

Accepted Answer

DOM is day-of-month (which date, 1–31) and DOW is day-of-week (which weekday, 0–7). When both are set to non-wildcard values, most cron implementations use OR logic: the job runs if the date matches OR the weekday matches.

`*`	every value
`*/n`	every n-th value
`a-b`	range a through b
`a,b,c`	list of values
`a-b/n`	range with step n
`n/m`	start at n, step m

`@yearly`	0 0 1 1 *
`@monthly`	0 0 1 * *
`@weekly`	0 0 * * 0
`@daily`	0 0 * * *
`@midnight`	0 0 * * *
`@hourly`	0 * * * *

Cron Expression Explainer

Quick Reference

Field positions

Syntax

Special strings

Cron Expression Explainer

Quick Reference

Field positions

Syntax

Special strings

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