YUM, it's not just good eatin', it's also for updating your RedHat (or CentOS) packages. https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-yum.html
What are the top 20 yummiest commands? http://www.tecmint.com/20-linux-yum-yellowdog-updater-modified-commands-for-package-mangement/