Installing MRI ruby

RubyInstaller If you are on Windows, there is a great project to help you install Ruby: RubyInstaller. It gives you everything you need to set up a full Ruby development environment on Windows. Also, you could go radical any just install jruby on windows

Just download it, run it, and you are done!

Arch Linux uses a package manager named pacman.

$ sudo pacman -S ruby

This should install the latest stable Ruby version.

NB: Other linux package installers are generally hopelessly out of date but might be OK if it is at least ruby-2.1.5 as with Debian, or you could go radical any just install jruby see below.

Homebrew (MacOS)

Many people on OS X use Homebrew as a package manager. It is really easy to get a newer version of Ruby using Homebrew:

$ brew install ruby

Managers

Many Rubyists use Ruby managers to manage multiple Rubies. They confer various advantages but are not officially supported. Their respective communities are very helpful, however do not use them unless you absolutely must, they are generally an absolute pain and not needed for JRubyArt (which ultimatley runs directly from java when using jruby-complete or from an installed jruby over which rvm and rbenv have no control over, you have been warned)

Installing jruby

For windows see JRuby wiki

For Arch Linux

$ sudo pacman -S jruby

This should install the latest stable JRuby version.

For Debian linux

Get the latest version from http://jruby.org/download

cd /opt
tar xzvf /pathToDownload/jruby-bin-9.x.x.x.tar.gz

You could the use the excellent update-alternatives to provide symbolic links to ruby, jruby, jirb jgem etc.

For MacOS user using the Homebrew as a package manager.

$ brew install jruby

This will again generally install the the latest jruby for you.

Managers

As far as I know rvm and rbenv are completely useless with jruby (further bundler is also as good as useless for JRubyArt)