Cloud9 (

It is not required to install Ruby on your own machine before the coding challenge. The easiest way to start using Ruby is to use Cloud9; it is free.

Here are the key steps:

  1. Go to and sign up.
  2. After you've signed up and confirmed your email, create a new workspace.
  3. When creating the workspace, choose "Blank" as the template.
  4. will provide a text editor for you to edit Ruby code in the browser. You can write Ruby code in the text editor. At the bottom is a console, you can run your code in the console.
  5. Run the following commands in the console. This will download the zipped file and unzip it for you. You should have a folder with the practice problems.


Here's a brief screencast that demonstrates the steps above:

You should be able to do all the prepwork using

Advanced Setup

You do not have to install Ruby on your own machine to do the prep-work. When starting out, you want to spend as much time coding and as little time as possible on banal setup tasks. Therefore, we highly recommend you use

Setting up Ruby on your machine can be a frustrating process. Setting up Ruby is not the same as programming; even great Rubyists can be frustrated by the hoops they have to jump through to setup their machine. Don't be discouraged if it's difficult!

To install Ruby on Windows, we recommend RubyInstaller. To install on Mac OSX, check out our dotfiles for more instructions.

Text Editor

You also need a proper code editor; Microsoft's notepad or Mac's TextEdit won't cut it. We recommend you use Atom.


A lot of Ruby development is done at the command line. Mac users can use

Windows users can run cmd, which is the Windows command line. Run it by pressing Windows Key-R (launches "run program") and typing cmd into the box.