No More Excuses! Using RVM to Play with Rails 3

Now that Rails 3.0 is out, it's high time to start using it. But what if you want to keep Rails 2.x around for your current projects? Fortunately, on OS X, there's a simple solution: RVM.

Once you've installed RVM, you'll need to install a version of ruby compatible with Rails 3. There are two choices: 1.8.7 and 1.9.2. Given its new features and speed improvements, 1.9.2 is the one to choose, unless you have particular dependencies on 1.8.7.

Installing 1.9.2 is simple: rvm install 1.9.2. This will download, compile, and install 1.9.2 to a .rvm folder in your home directory.

Once that's done, type rvm 1.9.2 to switch over and rvm info to confirm that you're now running 1.9.2. Note: this will only apply to the current terminal window, here's how to make it the default.

Type gem list and you should see just two gems: rake and bundler.

Now go ahead and install Rails 3: gem install rails. Confirm by way of rails --version and gem list.

That's it, you're done... Now have fun!

What to go back to your previous version of ruby? Just type: rvm system and you'll revert back to your standard ruby installation and the gems that went with it.