Hi,
Here i m with littel Unix Stuff.
Let's Talk About Unix CRON Jobs.
Crontab ( Cron Table ) Used to Schedule Commands to run at later time.
U Can Find info by Giving
man crontab, Here I m giving some info about it.You can execute crontab if your name appears in the file
/usr/lib/cron/cron.allow.
If that file does not exist,
you can usecrontab if your name does not appear in the file
/usr/lib/cron/cron.deny.
If only cron.deny exists and is empty, all users can use crontab.
If neither file exists, only the root user can use crontab.
Options for Crontab----------------------------------------------------------------------------
crontab -e To Edit crontab file.
crontab -l To Display crontab file.
crontab -r Remove crontab file.
----------------------------------------------------------------------------
A crontab file has five fields for specifying day , date and time followed by the command to be run at that interval.
Syntex For Crontab is* * * * * command to be executedU Can replace 1st
* with: hour (0 - 23)
U Can replace 2nd
* with: min (0 - 59)
U Can replace 3rd
* with: day of month (1 - 31)
U Can replace 4th
* with:month (1 - 12)
U Can replace 5th
* with:day of week (0 - 6) (Sunday=0)
Example for the Crontab :30 23 * * * rm /home/user/tmp/* ->it Indicates that, At 23:30 Daily all files from folder
/home/user/tmp/ will be removed.
30 23 * 10,12 1-5 rm /home/user/tmp/*->it Indicates that, At 23:30 every weekdays (Mon-Fri) in Oct & Dec all files from folder
/home/user/tmp/ will be removed.
Note: U Can put
# as a 1st Character of line & that line will not considered as Cron Job.