Installation

To install the Git version control system on a Gentoo server, follow the steps below:

1. Install the package dev-util/git
   # emerge -v dev-util/git
   When the above task finished, it printed out a message:
     * These additional scripts need some dependencies:

    *   git-quiltimport  : dev-util/quilt
    *   git-instaweb     : || ( www-servers/lighttpd www-servers/apache )

2. Now install the package dev-util/quilt. If you don't have lighttpd or apache, install that too.
   # emerge -pv dev-util/quilt
   When it finished, it printed out such message:
   * Messages for package dev-util/quilt-0.46:

    * If you intend to use the folding functionality (graphical illustration of the
    * patch stack) then you'll need to remerge this package with USE=graphviz.
    * To enable command-line completion for quilt, run:
    *
    *   eselect bashcomp enable quilt
    *
    * to install locally, or
    *
    *   eselect bashcomp enable --global quilt
    *
    * to install system-wide.

For installing Git on other systems, check the page Git Book - Installing Git.

Configuration

Just follow Git Book - Setup and Initialization:

$ git config --global user.name "Scott Chacon"
$ git config --global user.email "schacon@gmail.com"

That will set up a file in your home directory which may be used by any of your projects. By default that file is ~/.gitconfig and the contents will look like this:

[user]
        name = Scott Chacon
        email = schacon@gmail.com

If you want to override those values for a specific project (to use a work email address, for example), you can run the git config command without the --global option while in that project. This will add a [user] section like the one shown above to the .git/config file in your project's root directory.

And the follow the rest on Git Book.