If you want to schedule to run a command or script periodically, crontab will be a very useful tool. To add a command or a script to the crontab schedule, the command you need to use is:
sudo crontab -e
on 01/06/2013 – Made popular on 01/06/2013
I have a crontab file at /etc/crontab. I didn't place it there, it was already there, along with a lot of other files in /etc. However, when I type the command crontab -e, it creates a new file. I want it to look for crontab in /etc.