rvm install 1.9.3

Ruby (and needed base gems) for your selection will be installed shortly.
Before it happens, please read and execute the instructions below.
Please use a separate terminal to execute any additional commands.

  Notes for Mac OS X 10.8.1, Xcode 4.4.1.

For MacRuby: Install LLVM first.

For JRuby:  Install the JDK. See http://developer.apple.com/java/download/  # Current Java version "1.6.0_26"
For IronRuby: Install Mono >= 2.6
For Ruby 1.9.3: Install libksba # If using Homebrew, 'brew install libksba'

To use an RVM installed Ruby as default, instead of the system ruby:

    rvm install 1.8.7 # installs patch 357: closest supported version
    rvm system ; rvm gemset export system.gems ; rvm 1.8.7 ; rvm gemset import system.gems # migrate your gems
    rvm alias create default 1.8.7

And reopen your terminal windows.

Xcode and gcc:

Right now Ruby requires gcc to compile, but Xcode 4.2 and later no longer ship with gcc. Instead they ship with llvm-gcc (to which gcc is a symlink) and clang, neither of which are supported for building Ruby. Xcode 4.1 was the last version to ship gcc, which was /usr/bin/gcc-4.2.

Xcode 4.1 and earlier:
- Ruby will build fine.

Xcode 4.2 and later (including Command Line Tools for Xcode):
- If you have gcc-4.2 (and friends) from an earlier Xcode version, Ruby will build fine.
- If you don't have gcc-4.2, you have two options to get it:
 * Install apple-gcc42 from Homebrew
 * Install osx-gcc-installer

Homebrew:

  If you are using Homebrew, you can install the apple-gcc42 and required libraries from homebrew/dupes:

      brew update
      brew tap homebrew/dupes
      brew install autoconf automake apple-gcc42
      rvm pkg install openssl

  This can live side by side with an existing Xcode 4.2+ install or Command Line Tools for Xcode.

  osx-gcc-installer:

  If you don't use Homebrew, you can download and install osx-gcc-installer: https://github.com/kennethreitz/osx-gcc-installer.

  Warning: Installing osx-gcc-installer on top of a recent Xcode is known to cause problems, so you must uninstall Xcode before installing osx-gcc-installer. Afterwards you may install Xcode 4.2+ or Command Line Tools for Xcode if you desire.

  ** NOTE: Currently, Node.js is having issues building with osx-gcc-installer. The only fix is to install Xcode over osx-gcc-installer.