$ ruby -e "$(curl -fsSkL raw.github.com/mxcl/homebrew/go)"
$ brew doctor
$ cat > ~/.profile
homebrew=/usr/local/bin:/usr/local/sbin
export PATH=$homebrew:$PATH
$ source ~/.profile
$ brew update
$ brew tap homebrew/dupes
$ brew install autoconf automake apple-gcc42
$ brew install rbenv ruby-build
$ cat > ~/.profile
if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi
$ source ~/.profile
$ rbenv install 2.1.2
$ rbenv versions
* system (set by /Users/include/.rbenv/version
2.1.2
$ rbenv global 2.1.2
$ ruby --version
ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0]