See https://rvm.io/rvm/install/
curl -L get.rvm.io | bash -s stable
On OS X you can use RailsInstaller which will bring all dependencies for you: installer: https://github.com/railsinstaller/railsinstaller-nix/downloads background: http://www.engineyard.com/blog/2012/railsinstaller-for-os-x/