Map :W to :w in vim

One of the most annoying things about vim for me was that I frequently typed :W instead of :w. This is happens because the colon needs a shift, w doesn't.

So I mapped some commands in my .vimrc:

:command WQ wq
:command Wq wq
:command W w
:command Q q

Now if I am writing uppercase letters for that commands, the lower case commands will be executed.

Source: http://stackoverflow.com/questions/117150/can-i-re-map-commands-in-vim

Related protips:

Basic Vim commands - For getting started