crontab Syntax
# MIN HOUR DOM MON DOW COMMAND
*/5 * * * * /usr/local/bin/check.sh
30 3 * * * /usr/local/bin/backup.sh >> /var/log/backup.log 2>&1
@reboot /usr/local/bin/startup.sh💡 For critical jobs, use systemd timers — they have built-in retry and journald logging.