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Crontab Expression Tester

Test cron expressions and view next execution times. Essential for scheduling tasks!

Format: minute hour day month day-of-week

📋 Quick Examples

📖 Cron Expression Reference

FieldValuesSpecial Characters
Minute0-59* , - /
Hour0-23* , - /
Day of Month1-31* , - / ?
Month1-12 or JAN-DEC* , - /
Day of Week0-7 or SUN-SAT* , - / ?

Special Characters

  • * - Any value (every minute, every hour, etc.)
  • , - List separator (1,3,5)
  • - - Range (1-5)
  • / - Step values (*/5 = every 5 units)
  • ? - No specific value (used in day fields)

Common Examples

0 0 * * *Daily at midnight
0 */2 * * *Every 2 hours
30 9 * * 1-5Weekdays at 9:30 AM
0 0 1 * *First day of every month
0 0 * * 0Every Sunday at midnight
*/15 * * * *Every 15 minutes

Cron Expression Format​

* * * * *
│ │ │ │ │
│ │ │ │ └─ Day of week (0-7, 0 and 7 are Sunday)
│ │ │ └─── Month (1-12)
│ │ └───── Day of month (1-31)
│ └─────── Hour (0-23)
└───────── Minute (0-59)

Key Features​

  • Real-time parsing and validation
  • Human-readable descriptions
  • Next 10 execution times
  • Quick examples (daily, weekly, hourly, etc.)

Common Examples​

Every Minute​

* * * * *

Every Hour​

0 * * * *

Daily at Midnight​

0 0 * * *

Weekdays at 9 AM​

0 9 * * 1-5

Every 5 Minutes​

*/5 * * * *

Monthly (1st day at 3 AM)​

0 3 1 * *

Special Characters​

  • * - Any value
  • , - List separator (1,3,5)
  • - - Range (1-5)
  • / - Step values (*/5)

Use Cases​

1. Backups​

0 2 * * *  # Daily at 2 AM
0 2 * * 0  # Weekly on Sunday at 2 AM

2. Monitoring​

*/5 * * * *  # Health check every 5 minutes

3. Reports​

0 9 * * 1-5  # Weekday morning at 9 AM
0 17 * * 5   # Friday at 5 PM

Tips​

Linux Crontab​

crontab -e  # Edit crontab
crontab -l  # List crontab
crontab -r  # Remove crontab

Logging​

*/5 * * * * /script.sh >> /var/log/cron.log 2>&1

Prevent Concurrent Execution​

*/5 * * * * flock -n /tmp/my-cron.lock /script.sh