Ruby delights built into the language
I appreciate the Ruby love in this post, but it's worth pointing out that the author is clearly new to the language. I say that because he writes Ruby as if he's writing some other language, and not idiomatic Ruby.This:  dirp = Dir.open(".")
  for f in dirp
    case f
    when /\.rb\z/
      print f, "\n"
    else
      # do not print
    end
  end
  dirp.close

Could be made much more Ruby-native (and simpler!) as:  Dir.open('.').each do |f|
    puts f if f.match?(/\.rb\z/)
  end

My point isn't to play the "I know the language better than you, so nyah nyah" game, just to suggest that if the author likes Ruby as much as he says, he should learn it better.