Installation
Almost all distros have a form of cron installed by default. However, if you’re using a system that doesn’t have it installed, you can install it with the following commands:
For Ubuntu/Debian:
apt-get update
apt-get install cron
For Cent OS/Red Hat Linux:
yum update
yum install vixie-cron crontabs
You’ll need to make sure it runs in the background too:
chkconfig crond on
service crond start