Git setup

user: 

$ git config --global user.name "John Doe"
$ git config --global user.email johndoe@example.com

editor:

$ git config --global core.editor emacs

diff tool:

$ git config --global merge.tool vimdiff

list your settings

$ git config --list 

or check specific value

$ git config user.name

help:

$ git help <verb>
$ git <verb> --help
$ man git-<verb>  

example: 

$ git help config 

source: http://progit.org/book/ch1-5.html