crontab Configuration¶

Basic Operations¶

# Edit crontab
crontab -e

# View crontab
crontab -l

# Delete crontab
crontab -r

Basic Syntax¶

Format: minute hour day month day-of-week command

# Common practical examples
0 1 * * *           # Run daily at 1:00 AM
*/10 * * * *        # Run every 10 minutes
0 */2 * * *         # Run every 2 hours
0 9 * * 1-5         # Run weekdays at 9:00 AM
0 0 1 * *           # Run on the 1st of every month at midnight
0 2 * * 0           # Run every Sunday at 2:00 AM
30 5 1,15 * *       # Run on the 1st and 15th of every month at 5:30 AM

Special Characters¶

*      # All values
,      # Multiple values (e.g., 1,3,5)
-      # Range specification (e.g., 1-5)
/      # Interval specification (e.g., */10)

Log Output Configuration¶

# Output log to file
0 1 * * * /path/to/script.sh >> /var/log/cron.log 2>&1

# No email notification
0 1 * * * /path/to/script.sh > /dev/null 2>&1

Verify cron Operation¶

# Check cron service status
systemctl status cron

# Check cron log
tail -f /var/log/cron