Can I install Ruby on Rails 2.x and Ruby on Rails 3 side by side

Question

I have a Ubuntu rails enviroment for playing around with ROR. Right now I am running Rails 2.3.8.

I want to look into rails 3. Is it possible to run both dev enviro

Answer 1

For Windows users:

(I realize the asker uses Ubuntu, but this came up in the SERPs when I had a Windows-related question.)

You'll find that rvm isn't an option. You can use pik, however:

-- install the gem    
> gem install pik

-- run 'install' command to add the utility to your system
> pik_install [some dir in your PATH variable]

-- tell pik where your Ruby versions are
> pik add C:\Ruby187\bin
> pik add C:\Ruby193\bin

-- see which versions pik has under control and which one is actively being used
> pik list
* 187: ruby 1.8.7 (2011-06-30 patchlevel 352) [i386-mingw32]
  193: ruby 1.9.3p194 (2012-04-20) [i386-mingw32]

-- tell pik to use a different version
> pik use 193
> pik list
  187: ruby 1.8.7 (2011-06-30 patchlevel 352) [i386-mingw32]
* 193: ruby 1.9.3p194 (2012-04-20) [i386-mingw32]

-- confirm the change worked:
> ruby -v && rails -v
ruby 1.9.3p194 (2012-04-20) [i386-mingw32]
Rails 3.2.3

Answer 2

I would highly recommend Ruby Version Manager (rvm) - see this railscast for more information. This allows you to easily manage different versions of Ruby on the same machine. I believe this should also enable you to keep the different versions of Rails separate from each other, and allow you to switch between them easily - see this example from http://rvm.beginrescueend.com/gemsets/basics/ :

rvm 1.9.2-head
gem install rails -v 2.3.3

rvm gemset create rails222 rails126
Gemset 'rails222' created.
Gemset 'rails126' created.

rvm 1.9.2-head@rails222
gem install rails -v 2.2.2

rvm 1.9.2-head@rails126
gem install rails -v 1.2.6

Hope that helps!