execute (Gem::Commands::SetupCommand)

    # File lib/rubygems/commands/setup_command.rb, line 91
      def execute
        @verbose = Gem.configuration.really_verbose

        install_destdir = options[:destdir]

        unless install_destdir.empty? then
          ENV['GEM_HOME'] ||= File.join(install_destdir,
                                        Gem.default_dir.gsub(/^[a-zA-Z]:/, ''))
        end

        check_ruby_version

        if Gem.configuration.really_verbose then
          extend FileUtils::Verbose
        else
          extend FileUtils
        end

        lib_dir, bin_dir = make_destination_dirs install_destdir

        install_lib lib_dir

        install_executables bin_dir

        remove_old_bin_files bin_dir

        remove_source_caches install_destdir

        say "RubyGems #{Gem::VERSION} installed"

        install_rdoc

        say
        if @verbose then
          say "-" * 78
          say
        end

        release_notes = File.join Dir.pwd, 'History.txt'

        release_notes = if File.exist? release_notes then
                          open release_notes do |io|
                            text = io.gets '==='
                            text << io.gets('===')
                            text[0...-3]
                          end
                        else
                          "Oh-no! Unable to find release notes!"
                        end

        say release_notes

        say
        say "-" * 78
        say

        say "RubyGems installed the following executables:"
        say @bin_file_names.map { |name| "\t#{name}\n" }
        say

        unless @bin_file_names.grep(/#{File::SEPARATOR}gem$/) then
          say "If `gem` was installed by a previous RubyGems installation, you may need"
          say "to remove it by hand."
          say
        end
      end