Configuration Cron and Crontab

Cron is a program that perform tasks that have been scheduled based on the table crontab. Cron complete this task by himself awake every minute and check whether there is a jobs, which must be based on the table dijalankannya crontab. Please note the difference between cron same crontab. Cron is a program or daemon, while crontab is the name to the list of jobs, which will run by cron.

Crontab = Cron Table

File command structure Crontab
*    *    *    *    *    *    *
The sense is, for a star to:
1. Minute (0-59)
2. Hours (0-23) 0 = dinihari
3. Day (1-31)
4. Month (1-12)
5. Weekly (0-6) 0 = Week
6. User (optional)
7. Command / Command

To create a cron schedule, live type:
crontab -e
then enter what will be the schedule

Example 1:
0    5    23    *    *    /sbin/reboot
This means: the computer will reboot every 23 hours at 5:00

Example 2:
5    14    1    1,5    *    ping www.google.com
This means: Computer will ping each month of January and on 1 May at 14:05 hours.

It was also a problem, there is a computer that can not be ping, but I love bait in the first ping from another computer. Rather than continuously ping continue to ask, I just love the crontab every 5 minutes.
*/5    *    *    *    *    ping –c 7 10.10.1.248
This means: Computer will ping with 7 times counter to the computer with the IP 10.10.1.248 every 5 minutes.

Additional:
crontab -l   : see the list of cron-job
crontab -r   : remove the list of cron-job

However, CMIIW

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Tags: *nix, cron, crontab, Linux, schedule

15.Nov.08 Linux