Update built-in vim on Mac OS X

Like Eric, I used homebrew, but I used the default recipe. So:

brew install mercurial
brew install vim

And after restarting the terminal homebrew's vim should be the default. If not, you should update your $PATH so that /opt/homebrew/bin is before /usr/bin. E.g. add the following to your .profile:

export PATH=/opt/homebrew/bin:$PATH

Note: Previous versions of Homebrew did install to /usr/local, so in that case you have to use /usr/local/bin instead of /opt/homebrew/bin.

If I understand things correctly, you want to install over your existing Vim, for better or worse :-) This is a bad idea and it is not the "clean" way to do it. Why? Well, OS X expects that nothing will ever change in /usr/bin unbeknownst to it, so any time you overwrite stuff in there you risk breaking some intricate interdependency. And, Let's say you do break something -- there's no way to "undo" that damage. You will be sad and alone. You may have to reinstall OS X.

Part 1: A better idea

The "clean" way is to install in a separate place, and make the new binary higher priority in the $PATH. Here is how I recommend doing that:

$ # Create the directories you need
$ sudo mkdir -p /opt/local/bin
$ # Download, compile, and install the latest Vim
$ cd ~
$ hg clone https://bitbucket.org/vim-mirror/vim or git clone https://github.com/vim/vim.git
$ 
$ cd vim
$ ./configure --prefix=/opt/local
$ make
$ sudo make install
$ # Add the binary to your path, ahead of /usr/bin
$ echo 'PATH=/opt/local/bin:$PATH' >> ~/.bash_profile
$ # Reload bash_profile so the changes take effect in this window
$ source ~/.bash_profile

Voila! Now when we use vim we will be using the new one. But, to get back to our old configuration in the event of huge f*ckups, we can just delete the /opt directory.

$ which vim
/opt/local/bin/vim
$ vim --version | head -n 2
VIM - Vi IMproved 7.3 (2010 Aug 15, compiled Aug 27 2011 20:55:46)
MacOS X (unix) version

See how clean this is.

I recommend not to install in /usr/local/bin when you want to override binaries in /usr/bin, because by default OS X puts /usr/bin higher priority in $PATH than /usr/local/bin, and screwing with that opens its own can of worms.... So, that's what you SHOULD do.

Part 2: The "correct" answer (but a bad idea)

Assuming you're set on doing that, you are definitely on track. To install on top of your current installation, you need to set the "prefix" directory. That's done like this:

hg clone https://bitbucket.org/vim-mirror/vim or git clone https://github.com/vim/vim.git
cd vim
./configure --prefix=/usr
make
sudo make install

You can pass "configure" a few other options too, if you want. Do "./configure --help" to see them. I hope you've got a backup before you do it, though, in case something goes wrong....

Don't overwrite the built-in Vim.

Instead, install it from source in a different location or via Homebrew or MacPorts in their default location then add this line to your .bashrc or .profile:

alias vim='/path/to/your/own/vim'

and/or change your $PATH so that it looks into its location before the default location.

The best thing to do, in my opinion, is to simply download the latest MacVim which comes with a very complete vim executable and use it in Terminal.app like so.

alias vim='/Applications/MacVim.app/Contents/MacOS/Vim' # or something like that, YMMV