    # File lib/rubygems/commands/contents_command.rb, line 37
      def execute
        version = options[:version] || Gem::Requirement.default
        gem = get_one_gem_name

        s = options[:specdirs].map do |i|
          [i, File.join(i, "specifications")]
        end.flatten

        path_kind = if s.empty? then
                      s = Gem::SourceIndex.installed_spec_directories
                      "default gem paths"
                    else
                      "specified path"
                    end

        si = Gem::SourceIndex.from_gems_in(*s)

        gem_spec = si.search(/\A#{gem}\z/, version).last

        unless gem_spec then
          say "Unable to find gem '#{gem}' in #{path_kind}"

          if Gem.configuration.verbose then
            say "\nDirectories searched:"
            s.each { |dir| say dir }
          end

          terminate_interaction
        end

        files = options[:lib_only] ? gem_spec.lib_files : gem_spec.files
        files.each do |f|
          say File.join(gem_spec.full_gem_path, f)
        end
      end