This article explains why you should avoid using the version of Ruby bundled with Mac OS X and should instead install your own version of Ruby with RVM, the Ruby Version Manager.
Hands Off the System Ruby
Apple bundles the Ruby programming language with OS X. However, the main caveat for using the bundled version, called the system Ruby, is that Apple bundles Ruby for it’s own use. Therefore, it’s best not to make changes to the system Ruby.
You’ll know when you’re about to change the system Ruby when you need to prefix a gem installation with sudo, for example:
Another reason for not using the system Ruby is that it’s often several versions behind the latest stable version.
We will be setting up a Ruby on Rails development environment on Mac OS X 10.11 El Capitan. Older versions of OS X are mostly compatible so follow along as far as you can and then Google search for any problems you run into. There are plenty of people who have documented solutions for them. Hey, this isn't so bad. Mac OS X 10.4 has ruby and irb (interactive ruby) installed by default, so I was able to just type 'irb' and follow along with the examples. I'm starting to like this 'ruby' thing. Suddenly I don't feel like I'm being dragged across the floor trying to dig my nails into linoleum. No, this dog likes Ruby! Join Kevin Skoglund for an in-depth discussion in this video Ruby for Mac OS 10.x, part of Ruby on Rails 4 Essential Training. Lynda.com is now LinkedIn Learning! To access Lynda.com courses again, please join LinkedIn Learning. All the same Lynda.com content you know and love. As others have noted, OS X comes with various open source packages pre-installed. While this can be a nice convenience, the packages often are only updated to new versions as part of a major OS X release (like 10.5 to 10.6). Also, some packages are used elsewhere by other parts of OS X and there is no easy way to know which.
The Ruby Version Manager
A better alternative to using the system Ruby is to install Ruby with RVM, the Ruby Version Manager. RVM is a tool for installing different versions of Ruby itself. RVM has the following advantages:
RVM enables you to install multiple versions of Ruby and allows you to change which version you want to use.
RVM installs each version of Ruby in a hidden folder in your home folder so each version of Ruby you install doesn’t affect the system Ruby.
Gems installed by RVM-managed versions of Ruby are installed within the hidden folder in your home folder containing that version of Ruby.
You won’t need use sudo to install gems.
To check that you’re currently using the system Ruby, open Terminal and type the following:
If you’re using the system Ruby, OS X will respond with:
You can check which version of Ruby OS X is using with:
Installing RVM and Ruby
The RVM install page has comprehensive instructions for installing RVM that work on Mac OS X. I’ll provide the steps I used here.
The first step is to install the mpapis public key. However, as the install page notes, you might need gpg. Mac OS X doesn’t ship with gpg so before installing the public key, you’ll need to install gpg. I installed gpg with Homebrew:
After you’ve installed gpg, you can install the mpapis public key:
I've listed the mapis public key install command here for illustration. You should use the version on the RVM install page.
I chose to install RVM with the latest stable version of Ruby, which at the time was 2.2.0:
After the installation completes, close the Terminal window and open a new one to make sure that Terminal picks up any environment changes.
Ruby On Rails Mac Os X Install
Using RVM
You can list the versions of Ruby available to RVM with rvm list:
The rvm use command selects a version of Ruby:
You can check that you’re using an RVM-managed version of Ruby with:
OS X now responds with:
How To Update Mac Os X
which tells us we’re using version 2.2.0 and that version 2.2.0 has been installed in my home folder away from the system Ruby. You can confirm this by asking Ruby itself with:
The RVM-managed version of Ruby responds with:
As I mentioned earlier, gems installed with RVM-managed versions of Ruby are located with the Ruby. You can check where gems will be installed with:
Ruby On Rails Ide Mac Os X
The following lines of output shows that gems will be installed in the folder XXX.
Apple Mac Os X
To find out where a particular gem is installed, use the gem which command. For example, gem which jekyll locates the Jekyll gem: