Using Multiple Versions of Ruby At The Same Time

From RubyInside:

Ruby Version Manager ^{GitHub repo} (a.k.a. RVM) makes it ridiculously easy to install and switch between multiple Ruby versions on OS X and Linux. Over the last 24 hours, I’ve been playing with RVM and talking to creator Wayne E. Seguin and have been blown away with how cool (and simple) it is – you will definitely want to check this one out.

RVM’s most compelling feature is that it caters for six different distributions out of the box (MRI 1.8.6, MRI 1.8.7, 1.9.1, 1.9.2, Ruby Enterprise Edition 1.8.6, JRuby 1.3.1) and it’ll install them the first time you need to use them. RVM doesn’t mess up your current Ruby install – the RVM installed implementations are only activated manually by you and you can switch back to the “default” with one line.

It’s possible to install different patch levels if you like too and Wayne has put together a list of examples to show you the various things RVM can do from the command line (including gem management).