The ATrpms repository provides many bleeding edge software packages so if you have a development server where you install new apps this repo can be very useful. The instructions are not 100% clear about how to install this repository on CentOS Linux which would also be the same on RedHat Linux but not on Fedora Linux. Anyhow the example used on the ATrpms site relates to Fedora so the repo file needs to be modified to work on CentOS as noted below.
Installing the EPEL repository on CentOS Linux is easy to do so the below is simply a reference point if needed by anyone. EPEL stands for Extra Packages for Enterprise Linux and is a community based repository that was created for add-on Fedora Linux packages. There are many cases where installation instructions assume that the EPEL repo is already installed so if you run into an error because of a missing package or dependency package the EPEL repository is a great place to start. Below I have listed the i386(32-bit) and x86_64(64-bit) EPEL repository package list links which will allow you to easily verify that the packages you need are available before installing the EPEL repository. After the EPEL repository package list links there are separate commands listed to install the EPEL repository on 32-bit CentOS Linux 5.X and to install the EPEL repository on 64-bit CentOS Linux 5.X.
Typically the “which” command is installed by default though depending on what Linux distribution and what packages you decided to install there is a possibility the command is not installed. Installing which is easy on any distribution as the package is literally just called “which”. Below is a brief explanation of the error you could get if which is not installed and information on how to install the which package using the yum package manager on CentOS.
Sometimes after upgrading your RPM packages with YUM there will be new configuration files generated. These files have .rpmnew tacked onto the end and are created this way so they do not overwrite any configuration file changes you have made. You can find all of the .rpmnew files by running the following command from your shell.
find /etc /var -name *.rpmnew