Overview

git config --global user.email you@yourdomain.example.com
git config --global user.name "Your Name Comes Here"

In detail

This is to tell git_ who you are, for labeling any changes you make to the code. The simplest way to do this is from the command line:

git config --global user.email you@yourdomain.example.com
git config --global user.name "Your Name Comes Here"

This will write the settings into your git configuration file - a file called .gitconfig in your home directory.

Advanced git configuration

You might well benefit from some aliases to common commands.

For example, you might well want to be able to shorten git checkout to git co.

The easiest way to do this, is to create a .gitconfig file in your home directory, with contents like this:

[core]
        editor = emacs
[user]
        email = you@yourdomain.example.com
        name = Your Name Comes Here
[alias]
        st = status
        stat = status
        co = checkout
[color]
        diff = auto
        status = true

(of course you'll need to set your email and name, and may want to set your editor). If you prefer, you can do the same thing from the command line:

git config --global core.editor emacs
git config --global user.email you@yourdomain.example.com
git config --global user.name "Your Name Comes Here"
git config --global alias.st status
git config --global alias.stat status
git config --global alias.co checkout
git config --global color.diff auto
git config --global color.status true

These commands will write to your user's git configuration file ~/.gitconfig.

To set up on another computer, you can copy your ~/.gitconfig file, or run the commands above.

Other configuration recommended by Yarik

In your ~/.gitconfig file alias section:

wdiff = diff --color-words

so that git wdiff gives a nicely formatted output of the diff.

To enforce summaries when doing merges(~/.gitconfig file again):

[merge]
   summary = true