frozen_string_literals.rb

comment = "# frozen_string_literal: true\n"
filemode = "r+"
dirs = Dir[Rails.root.join('spec/**/*.rb').to_s] +  Dir[Rails.root.join('lib/**/*.rake').to_s] + Dir[Rails.root.join('lib/**/*.rb').to_s]
dirs.each do |filename|
  contents = File.open(filename, "r") do |f|
    f.read
  end
  contents = comment + contents

  File.open(filename, "w") do |f|
    f.write contents
  end
end