Crontab Syntax with Practical Examples

03 June 2025

Edit your jobs with crontab -e and list them with crontab -l.

# .---------------- minute (0-59)
# |  .------------- hour (0-23)
# |  |  .---------- day of month (1-31)
# |  |  |  .------- month (1-12)
# |  |  |  |  .---- day of week (0-7, Sunday is 0 or 7)
# |  |  |  |  |
# *  *  *  *  *  command_to_run

Examples:

15 10 * * *   /path/script.sh          # every day at 10:15
*/5 * * * *   /path/script.sh          # every 5 minutes
0 3 * * 0     /path/backup.sh          # Sundays at 03:00
0 8 1 * *     /path/report.sh          # 1st of every month at 08:00
@reboot       /path/start.sh           # at boot

Log the output (otherwise errors are lost):

15 10 * * * /path/script.sh >> /var/log/script.log 2>&1

If a job doesn't run:

Cron has a minimal PATH: use absolute paths to commands and scripts.
% has a special meaning in crontab, escape it as \%.
Check the logs: grep CRON /var/log/syslog or journalctl -u cron.

Handy checker: crontab.guru.