CSL: Crontabs
cron
utility as well as providing CS-specific details.It is possible for crontabs to be accidentally erased from system areas. Therefore, it is a good practice to keep a copy of any of your crontabs in your home directory. We also recommend running your crontabs from the centralized server cron.cs.duke.edu, as opposed to individual desktop machines; if the desktop machines break or are replaced, your cron jobs will not be saved. Below are examples of saving your existing crontabs and loading your saved crontabs into your home directory:
Saving existing crontabs
user@cron> crontab -l > crontab.saveLoading saved crontabs
user@cron> crontab < crontab.savePlease see the crontab man page for more information.
Sample crontab entry
Here is a sample crontab
entry:
0 0,8,12,16,20 * * * /home/user/bin/myscript
This entry tells the cron
utility to run myscript
on the hour at midnight, 8am, noon, 4pm, and 8pm every day of the week. For more information about the time format used, please see the crontab configuration man page for more information. If the script produces any output, cron
will email you the result.