📅 Cron Expression Generator

📚 User Guide

What is Cron?

Cron is a time-based job scheduler in Unix/Linux systems. Cron expressions are used to define the execution schedule for tasks.

Cron Expression Format

* * * * *
│ │ │ │ │
│ │ │ │ └─ Weekday (0-6, 0=Sunday)
│ │ │ └─── Month (1-12)
│ │ └───── Day (1-31)
│ └─────── Hour (0-23)
└───────── Minute (0-59)
                

Special Characters

• * - Any value, matches all
• ? - No specific value (only for day and weekday)
• , - List separator, e.g. 1,3,5
• - - Range, e.g. 1-5
• / - Step value, e.g. */5 means every 5 units

Common Examples

• 0 0 * * * - Daily at midnight
• 0 9 * * 1-5 - Weekdays at 9AM
• */5 * * * * - Every 5 minutes
• 0 */2 * * * - Every 2 hours
• 0 0 1 * * - First day of each month at midnight
• 0 0 * * 0 - Every Sunday at midnight
• 30 9 * * 1-5 - Weekdays at 9:30AM
• 0 12 * * * - Daily at noon

Important Notes

• Day and weekday cannot both use * - at least one must use ?
• Some systems support 6 or 7 field formats (including seconds or year)
• Different Cron implementations may vary
• Always test expressions in your actual environment

Use Cases

• Scheduled data backups
• Automated email sending
• Periodic log cleanup
• Data synchronization
• Report generation