# Installation on RedHat 5.6 or CentOS 5.6

To install Cain, first ensure that you have a C++ compiler and the appropriate Python packages. (See below.) Then follow the instructions for installation on linux/unix.

C++ compiler.
First ensure that you have a C++ compiler. In the Package Manager install `Development Libraries` and `Development Tools`.

Enthought Python Distribution.
Because RedHat 5.6 and CentOS 5.6 are "enterprise" Linux distributions, they have an old version of Python (version 2.4.3). It is recommended that you upgrade to a more recent version. The easiest approach is to install the Enthought Python Distribution. It includes all of the packages that Cain requires. There is a free version for those associated with educational institutions. Download and save the Enthought Python Distribution installer file. You may either install for all users or just for your own use. Let's assume the former. (If you do not have administrator privileges, you can install EPD in your home directory.) In a terminal switch to superuser with "su". Start the installation with something like "sh epd-7.0-2-rh5-x86.sh". During installation you will be queried for an installation location. Choose something appropriate like "/usr/lib/python2.7". After the installation you will need to prepend the path to EPD python to your PATH environment variable. To do this execute "export PATH=/usr/lib/python2.7/bin:$PATH" in a terminal. It will be convenient to add this definition to your .bashrc or .bash_profile in your home directory.