Installing rbx 2.2.1

$ rbenv install rbx-2.2.1
$ gem install rubysl bundler

Rubinus does not come with the Ruby standard library, it must be installed as a gem.

$ rbenv install rbx-2.2.1
$ ruby -v

  rbenv: bundle: command not found

$ gem install bundler

  Fetching: bundler-1.5.1.gem (100%)
  Successfully installed bundler-1.5.1
  Parsing documentation for bundler-1.5.1
  An exception occurred running

      Could not find 'rubysl-tracer' (~> 2.0) among 101 total gem(s)