keepgoing (rubygems): This gem is intended for use in a single file Ruby script that uses bundler/inline. You start your script once with `ruby your-script.rb` and keepgoing will take control, and re-run your script every time you save your script. You can concentrate on tinkering, while keepgoing will, well keep going, providing you with a fast and effortless feedback loop for your ruby experiments. 
Keywords: repl|ruby