Red Hat Enterprise Linux / CentOS Linux Enable EPEL (Extra Packages for Enterprise Linux) Repository

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http://www.cyberciti.biz/faq/rhel-fedora-centos-linux-enable-epel-repo/
Q. How do I enable EPEL (Extra Packages for Enterprise Linux) repo and install the packages under RHEL / CentOS Linux?

A. EPEL (Extra Packages for Enterprise Linux) is a volunteer-based community effort from the Fedora project to create a repository of high-quality add-on packages that complement the Fedora-based Red Hat Enterprise Linux (RHEL) and its compatible spinoffs, such as CentOS and Scientific Linux.
EPEL provide lots of packages for CentOS / RHEL, It is not part of RedHat or CentOS but is designed to work with these major distributions. Please note that EPEL only provides free and open source software unencumbered by patents or any legal issues. In short you will not find mp3, dvd and music / media player under EPEL. However, you will find many programs related to networking, monitoring, sys admin, programming and so on.
Packages are supplied in RPM format and in most cases are ready to use. Beware that some packages may break something and you should not blindly install those packages.

How do I enable EPEL?

Simply type the following command as root user:
# rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm
List new repo:
# yum repolist
Sample output:

Loading "skip-broken" plugin
Loading "fastestmirror" plugin
repo id              repo name                                 status
addons               CentOS-5 - Addons                         enabled
base                 CentOS-5 - Base                           enabled
epel                 Extra Packages for Enterprise Linux 5 -   enabled
extras               CentOS-5 - Extras                         enabled
updates              CentOS-5 - Updates                        enabled

Once installed use yum command to list, view and install the packages:
# yum search package-name
# yum install package-name
See how to use yum command for installing and searching packages using various repos.