Cron

From Linux Solutions

Cron executes a command at a certain time.

You can use

crontab -e

to tell cron what should be executed when. You get a vi. Every line specifies one time and one command:

Example:

# m     h               dom     mon     dow     command
6       10,14,22        *       *       *       /root/runbackup

The script /root/runbackup is executed by cron an 10:06, 14:06, and 22:06 every day, every month.

Fields:

• m: minute
• h: hour
• dom: day of month
• mon: month
• dow: day of week
• command

Special Expressions:

• "*" indicates, that it is not specified. It means, that the command is executed e.g. every hour.

• You can specify more than one value by separating them with ","

• All lines which begin with "#" are ignored. They are comments.