require -> require_relative

require_changer.rb

require 'pathname'
Pathname('./lib').children.select(&:directory?).map(&:basename).each do |name|
  Dir["./lib/#{name}/**/*.rb"].each do |path|
    begin
      code = File.read(path)
      code.gsub!(%r{^(\s*)require (['"])#{name}/([\w/]*)['"]}) do
        relative_path = Pathname("./lib/#{name}/#{$3}.rb").relative_path_from(Pathname(path).dirname)
        %Q{#{$1}require_relative #{$2}#{relative_path.to_s[0..-4]}#{$2}}
      end
      File.write(path, code)
    rescue Exception => e
      puts "Error while processing #{path}:", e
    end
  end
end