install_rubygems

# File lib/rubygems/commands/update_command.rb, line 148
  def install_rubygems version # :nodoc:
    args = update_rubygems_arguments

    update_dir = File.join Gem.dir, 'gems', "rubygems-update-#{version}"

    Dir.chdir update_dir do
      say "Installing RubyGems #{version}"

      # Make sure old rubygems isn't loaded
      old = ENV["RUBYOPT"]
      ENV.delete("RUBYOPT") if old
      installed = system Gem.ruby, 'setup.rb', *args
      say "RubyGems system software updated" if installed
      ENV["RUBYOPT"] = old if old
    end
  end