tabs_to_spaces.rb

%w(rb js erb).each do |format|
  Dir.glob("app/**/*.#{format}").each do |file|
    if File.file? file
      puts file
      f = File.open(file, "r:UTF-8")
      text = f.read
      new_text = text.gsub(/\t/, '  ')
      
      File.open(file, "w:UTF-8") do |file|
        file.puts new_text
      end
    end
  end
end