Crontab Explainer

Read a crontab line and understand its schedule and command in plain English.

Decoding a crontab entry

A crontab is the file that schedules recurring jobs on Unix systems, and each line pairs a five-field cron schedule with a command to run. This explains a crontab line in plain English — both when it runs and, where present, what it runs — so you can audit a server's scheduled jobs without deciphering the terse syntax by hand.

Paste a crontab line and its meaning is explained.

Reading a real crontab

Real crontabs have a few extras beyond a bare cron expression: comments, environment settings at the top, and special shortcuts like the reboot keyword that runs a job at startup. Being able to read a whole crontab line back in plain language is how you check that a server is doing what you think — a surprising number of production surprises come from a scheduled job that runs more or less often than someone assumed. To build a schedule from scratch instead of reading one, a cron builder assembles the expression for you.

Frequently asked questions

What is a crontab?

The file that schedules recurring jobs on Unix systems, each line pairing a cron schedule with a command to run.

What are special entries like @reboot?

Shortcuts crontabs allow — @reboot runs a job at startup, and others stand in for common schedules like daily or hourly.

Is anything uploaded?

No. The explanation happens in your browser.

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