This new release of RubyStack includes RVM, a command-line tool which allows you to easily install, manage, and work with multiple Ruby environments from interpreters to sets of gems. This is convenient if you need to maintain multiple projects, dependent on different Ruby versions.
To install different Ruby versions it is necessary to have already installed the main compilation tools. These tools are already included inside our RubyStack Virtual Machines and Amazon Cloud Images. If you are using the native installer, you can check the RVM requirements running the following command:
$ rvm requirements
You can list the installed Ruby versions and use one of them. RubyStack 3.2.3-0 installs and configures Ruby 1.9.3-p194.
$ rvm use system
$ ruby --version
ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]
$ rvm install ruby-1.8.7-p358
You can find more info at BitNami RVM wiki and at the official RVM site.
For Windows users, RubyStack now ships DevKit. It is a toolkit that makes it easy to build and use native C/C++ extensions for Ruby on Windows like JSON, Thin and others.