Install git

Overview

Debian / Ubuntu sudo apt-get install git
Fedora sudo yum install git-core
Windows Download and install msysGit_
OS X Use the git-osx-installer_

In detail

See the git page for the most recent information.

Have a look at the github install help pages available from `github help`_

There are good instructions here: http://book.git-scm.com/2_installing_git.html