is it possible to make rails 2 the default instead of rails 3 on my mac?
Is it possible to make Rails 2 the default rails on my mac?
If you only wish to install rails 2, then specify the version you want when installing the gem
gem install rails-2.3.5
If you want to maintain different versions of rails, then you probably also want to maintain different versions of ruby. In that case, rvm is your friend.
Whenever you need to have couple of rails env RVM is always a good idea.