# using Homebrew

PREFIX=$(brew --prefix)

# do this to get just the npm recipe from my homebrew fork.
cd $PREFIX
git remote add isaacs git://github.com/isaacs/homebrew.git
git fetch -a isaacs
git checkout isaacs/master -- Library/Formula/npm.rb

# alternatively, you could also do this if you prefer to avoid git:
# curl https://github.com/isaacs/homebrew/raw/master/Library/Formula/npm.rb > $PREFIX/Library/Formula/npm.rb

brew install npm

# now do ALL the things that it says to do, or it won't work properly!