The *.tbz
that you downloaded from the official page contains a mvim
script.
Once you have moved that script somewhere in your $PATH
you can start the MacVim GUI like this:
$ mvim filename
and the MacVim CLI like that:
$ mvim -v filename
From there the only thing you need is to change your alias to point to mvim
:
alias vim='mvim -v'
The original built-in Vim and its runtime files stay untouched, MacVim uses its own runtime files located in the MacVim.app
bundle and both honor your personal config (assuming they are located where they should be: ~/.vimrc
and ~/.vim/
).
Quick, clean and painless.