Environment

All the sample programs have been tested on OS X with Ruby 1.9.2. Some of the code runs differently depending on your operating system (especially on Windows machines). I’ll mention the differences as we go along.

Throughout this book, we’ll do lots of experiments using the interactive Ruby shell (irb). When invoking irb, we pass the --prompt simple option to switch the command prompt to a simpler version (>>). Also, we have omitted some of the output prompts (=>) for a more concise display. Finally, you may want to specify --noreadline if you are an OS X user and experience problems using dRuby from irb (for more details, see ​OS X and readline​).