To use co in place of the more verbose checkout command:
$ git config –global alias.co checkout
Set the editor Git will use for commit messages. If you use a graphical editor such as Sublime Text, TextMate, gVim, or MacVim, you need to use a flag to make sure that the editor stays attached to the shell instead of detaching immediately:16
$ git config –global core.editor “subl -w”
Replace “subl -w” with “mate -w” for TextMate, “gvim -f” for gVim, or “mvim -f” for MacVim.