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DevOps & Automation ReferenceUpdated: 2026-11-05

Cron Job Expressions, Crontab Syntax & Scheduling Cheat Sheet

Quick lookup guide for the 5-field cron syntax, special character operators (*, /, -, ,), and common schedule recipes.

Cron is the time-based job scheduler standard across Unix-like computer operating systems. Configured through crontab files, cron executes scripts, database backups, and health checks at fixed dates or recurring intervals. This reference card breaks down the standard 5-field cron format and tested schedule expressions.

Table of Contents

Standard 5-Field Crontab StructureSpecial Operators DecodedCopy-Paste Production Cron Recipes

Standard 5-Field Crontab Structure

The 5 position fields that define an execution schedule.

Field PositionField NameAllowed ValuesSpecial Characters Allowed
1Minute0 - 59`*` `,` `-` `/`
2Hour0 - 23 (24h format)`*` `,` `-` `/`
3Day of Month1 - 31`*` `,` `-` `/` `L` `W`
4Month1 - 12 (or JAN-DEC)`*` `,` `-` `/`
5Day of Week0 - 7 (0 & 7 are Sunday; or SUN-SAT)`*` `,` `-` `/` `L` `#`

Special Operators Decoded

How mathematical symbols alter scheduling rules.

SymbolNameMeaning & Example
`*`Asterisk (Wildcard)Matches every possible value. `* * * * *` runs every single minute.
`,`Comma (List)Defines an explicit list of values. `15,45 * * * *` runs at minute 15 and 45.
`-`Hyphen (Range)Specifies an inclusive range. `0 9-17 * * *` runs hourly from 9 AM through 5 PM.
`/`Slash (Step)Specifies step intervals. `*/15 * * * *` runs every 15 minutes.

Copy-Paste Production Cron Recipes

Frequently used schedule expressions for servers, CI/CD, and database backups.

Every 5 Minutes (Health Check / Queue Consumer)cron
*/5 * * * *
Executes at 00:00, 00:05, 00:10, 00:15... every hour of every day.
Every Day at Midnight (00:00 UTC Daily Maintenance)cron
0 0 * * *
Standard schedule for daily database snapshots and log archiving.
Every Monday at 9:00 AM (Weekly Team Digest)cron
0 9 * * 1
Executes once a week on Monday morning at 09:00.
First Day of Every Month at 01:00 AM (Monthly Invoicing / Reports)cron
0 1 1 * *
Runs on the 1st of every month at 1:00 AM.

Interactive Client-Side Tools for this Guide

Test and run these patterns directly inside your browser with zero server uploads:

Online Cron Expression Generator & Human Explainer

Build cron schedule strings interactively or translate cryptic expressions into plain English. View next estimated runtimes with zero server latency.

Open Tool

Linux Chmod Permissions Calculator & Command Generator

Calculate numerical and symbolic Linux file permissions with an interactive permission matrix. Generate terminal commands without memorizing octal values.

Open Tool

Unix Timestamp Converter (Epoch to Human Date)

Convert seconds and milliseconds epoch timestamps to human-readable datetime formats across all timezones.

Open Tool

Frequently Asked Questions

What time zone does cron use?

Cron executes based on your server's system time zone. In cloud environments (AWS, GCP), servers are almost universally configured to UTC to prevent daylight saving time clock jumps.

How can I build and preview cron schedules interactively?

Use DocSwift's free Cron Generator. Pick intervals using visual dropdowns to generate valid crontab strings with natural language explanations.

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