bundler_libs.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'pathname'
gem 'bundler'

require 'bundler'
files = Bundler.load.specs.map do |spec| 
  path = Pathname.new(spec.full_gem_path)
  spec.lib_files.map {|file| path.join(file).to_s }
end.flatten.grep /\.rb$/i
puts files.join(" ")