Ruby is an important tool to have around, Mac OS X already comes bundled with it, but sometimes you need a different version. Mavericks now comes with Ruby 2.0.0-p195, any previous ones comes with 1.8.7 which is very close to end of life. There are lots of alternative to install multiple version of Ruby on your workstation, rvm or rbenv works well for this job but Postmodern have another angle to this problem. Quite similar to the Arch Linux Kiss (Keep It Simple, Stupid) philosophy, chruby is a deadly simple tool to do just that by updating the environment variables: $RUBY_ROOT, $RUBY_ENGINE, $RUBY_VERSION, $GEM_ROOT, $GEM_HOME, $GEM_PATH and $RUBYOPT in just 90 lines of codes. Let’s details how you can install it on your Mac.

Dependencies

We will use brew to install chruby. This tool require the Xcode Command Line Tools from Apple. First install it from

https://developer.apple.com/downloads/. You’ll need a Developper ID but it’s free and easy to get from this link, just click on Register. If you already have an Apple ID, you can use it.

Check if Xcode Command Line Tools is installed.

xcode-select -version

You can now install brew with by running this command which will pause before doing anything on your machine

ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

Check if brew looks good

brew doctor

Use brew to install Ruby dependencies

brew install gdbm libffi libyaml openssl readline

chruby installation

To install chruby, just type

brew install chruby

And add the following line to your .bashrc or .zshrc

source /usr/local/opt/chruby/share/chruby/chruby.sh

To make things easier, you can install ruby-install, this tool automate Ruby installation

brew install ruby-install

Check the installation went well

brew list

Ruby 1.9.3 installation

Now you can Install any newer Ruby version like this

ruby-install ruby 1.9.3

Use chruby to Switch to it

chruby 1.9.3

Check all your Gems will be installed in your User directory

gem env

You can also check your environment variables

env

You can go back to your system Ruby using

chruby system

We wish you all a Merry Christmas. Have Fun with Ruby on Mac.