Скачать или смотреть Linux - Job Automation crontab

CRON:
The importance of the job scheduling is that the critical tasks like taking backups, which the clients usually wants to be taken in nights, can easily be performed without the intervention of the administrator by scheduling a cron job.
6 fields
* * * * Command to be execute

1. Minutes (0-59)
2. Hours (0-23)
3. Day of the month (1-31)
4. Month of the Year (1-12) JAN /FEB...
5. Day of the week (0-7)
(0, 7- Sunday)
6. Command

Config. File -- /etc/crontab

crobtab -l -- to display the cron jobs
crontab -e -- to create a cron jobs
crontab -r -- to remove the cron jobs
crontab -l -u usernaame -- to seee the cron jobs of a particular user
cat /var/log/cron - cronjob log