Install EPEL repo for CentOS 6

From shell -

Navigate to https://fedoraproject.org/wiki/EPEL

Grab the latest version of the EL6 Repo - copy it to your clipboard, and use it in the following command

rpm -i <pasted link>

Example

rpm -i http://mirror.us.leaseweb.net/epel/6/i386/epel-release-6-8.noarch.rpm

After installed, enable the testing repo, if needed.  S3cmd needs the testing repo, for example

nano /etc/yum.repos.d/epel-testing.repo

Change "enabled=0" to "enabled=1"

ctrl-x to save.