A script to install the EPEL repo if it isn't installed.

redhat5.sh

#!/bin/bash

if [ ! -f /etc/yum.repos.d/epel.repo ]
then
    wget http://mirror.es.its.nyu.edu/epel/5/i386/epel-release-5-4.noarch.rpm
    yum localinstall epel-release-5-4.noarch.rpm
    rm -f epel-release-5-4.noarch.rpm
    sed -i "s/enabled=1/enabled=0/g" /etc/yum.repos.d/epel.repo
fi

redhat6.sh

#!/bin/bash

if [ ! -f /etc/yum.repos.d/epel.repo ]
then
    wget http://mirror.pnl.gov/epel/6/i386/epel-release-6-7.noarch.rpm
    yum localinstall epel-release-6-7.noarch.rpm
    rm -f epel-release-6-7.noarch.rpm
    sed -i "s/enabled=1/enabled=0/g" /etc/yum.repos.d/epel.repo
fi