execute (Gem::Commands::WhichCommand)

    # File lib/rubygems/commands/which_command.rb, line 34
      def execute
        searcher = Gem::GemPathSearcher.new

        options[:args].each do |arg|
          dirs = $LOAD_PATH
          spec = searcher.find arg

          if spec then
            if options[:search_gems_first] then
              dirs = gem_paths(spec) + $LOAD_PATH
            else
              dirs = $LOAD_PATH + gem_paths(spec)
            end

            say "(checking gem #{spec.full_name} for #{arg})" if
              Gem.configuration.verbose and $stdout.tty?
          end

          paths = find_paths arg, dirs

          if paths.empty? then
            say "Can't find ruby library file or shared library #{arg}"
          else
            say paths
          end
        end
      end