-- CentOS 6 --
wget -N -P /tmp https://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-6  https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
rpm --import /tmp/RPM-GPG-KEY-EPEL-6
sudo rpm -i /tmp/epel-release-latest-6.noarch.rpm

-- CentOS 7 --
yum install epel-release

-- Amazon Linux--
run "sudo yum-config-manager --enable epel"
and "sudo rpmkeys --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6"

== URLs ==
http://mirror.internode.on.net/pub/epel/5/i386/repoview/epel-release.html 
http://mirror.internode.on.net/pub/epel/6/i386/repoview/epel-release.html 

https://dl.fedoraproject.org/pub/epel/epel-release-latest-5.noarch.rpm 
https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm