Once you have both the cmake and the cmake3 package installed on your machine, you can use update-alternatives to switch between both packages.

Use the alternatives command to register both installations:

$ sudo alternatives --install /usr/local/bin/cmake cmake /usr/bin/cmake 10 \
--slave /usr/local/bin/ctest ctest /usr/bin/ctest \
--slave /usr/local/bin/cpack cpack /usr/bin/cpack \
--slave /usr/local/bin/ccmake ccmake /usr/bin/ccmake \
--family cmake

$ sudo alternatives --install /usr/local/bin/cmake cmake /usr/bin/cmake3 20 \
--slave /usr/local/bin/ctest ctest /usr/bin/ctest3 \
--slave /usr/local/bin/cpack cpack /usr/bin/cpack3 \
--slave /usr/local/bin/ccmake ccmake /usr/bin/ccmake3 \
--family cmake

After these two commands, cmake3 will be invoked by default, when you enter cmake from a bash prompt or start a bash script. The commands also take care of registering a few secondary commands like ctest which need to be switched along with cmake.

If you need to switch back to cmake 2.8 as the default, run the following command:

$ sudo alternatives --config cmake

There are 2 programs which provide 'cmake'.

  Selection    Command
-----------------------------------------------
   1           cmake (/usr/bin/cmake)
*+ 2           cmake (/usr/bin/cmake3)

Enter to keep the current selection[+], or type selection number: 1

You don't say but what versions are you getting and what versions do you expect?

What repositories do I have?

You can find out what repositories your system is configured to query using this command:

$ yum repolist | expand
Loaded plugins: fastestmirror, priorities, refresh-packagekit
Loading mirror speeds from cached hostfile
 * base: centos.mirror.constant.com
 * epel: mirror.steadfast.net
 * extras: mirror.symnds.com
 * updates: bay.uchicago.edu
77 packages excluded due to repository priority protections
repo id         repo name                                               status
base            CentOS-6 - Base                                         6,297+70
epel            Extra Packages for Enterprise Linux 6 - x86_64            10,246
extras          CentOS-6 - Extras                                            7+7
updates         CentOS-6 - Updates                                           314
repolist: 16,864

Package info

You can query any package whether it's installed or not using yum info <pkg>.

$ yum info cmake
Loaded plugins: fastestmirror, priorities, refresh-packagekit
Loading mirror speeds from cached hostfile
 * base: centos.mirror.constant.com
 * epel: mirror.steadfast.net
 * extras: mirror.symnds.com
 * updates: bay.uchicago.edu
77 packages excluded due to repository priority protections
Installed Packages
Name        : cmake
Arch        : x86_64
Version     : 2.6.4
Release     : 5.el6
Size        : 18 M
Repo        : installed
From repo   : base
Summary     : Cross-platform make system
URL         : http://www.cmake.org
License     : BSD
Description : CMake is used to control the software compilation process using simple
            : platform and compiler independent configuration files. CMake generates
            : native makefiles and workspaces that can be used in the compiler
            : environment of your choice. CMake is quite sophisticated: it is possible
            : to support complex environments requiring system configuration, pre-processor
            : generation, code generation, and template instantiation.

Package's URL

You can find out where a RPM is being downloaded from using the repoquery command.

$ repoquery --location cmake
http://centos.mirrors.hoobly.com/6.5/os/x86_64/Packages/cmake-2.6.4-5.el6.x86_64.rpm

Which is part of this repository:

$ repoquery -i cmake | grep Repos
Repository  : base

So this is a base repository to the CentOS distro that's providing this package.

What other repositories have it?

You can query what repositories contain a specific package (at least most of the major repos) using pkgs.org.

• http://pkgs.org/search/?query=cmake&type=smart

According to this list the EPEL repo has the latest version pre-built. The version of this package is as follows: cmake 28-2.8.11.2-1.