Dealing with Crontab

Schedule tasks under Linux is an powerful procedure which is used by almost everyone, and to do this using program called cron. more about it here .


Procedure :

make a new text file, and enter this line in that text file like the below :-

crontab myfirstjob

Formatting crontab file :-

what this file contains

Number	Meaning	Allowed range
1	Minutes	0-59
2	Hours	0-23
3	Days	1-31
4	Months	1-12 OR First 3 letters of the Month name
5	Days of the week	0-7 OR First 3 letters of the Day name
6	Name of the program	Any program

Some useful command can be used with cron :-

Show all the task running under cron.

crontab -l

crontab -e

Some example from crontab file :-

# Minute   Hour      Day of Month       Month                 Day of Week        Command  
# (0-59)     (0-23)     (1-31)             (1-12 or Jan-Dec)    (0-6 or Sun-Sat)              
    0               12           *                             *                         *            /u01/backup.sh

For more example about crontab press here

Cheers
Osama Mustafa