# File lib/chef/knife/cookbook_site_install.rb, line 56
      def run
        extend Chef::Mixin::ShellOut

        if config[:cookbook_path]
          Chef::Config[:cookbook_path] = config[:cookbook_path]
        else
          config[:cookbook_path] = Chef::Config[:cookbook_path]
        end

        @cookbook_name = parse_name_args!
        # Check to ensure we have a valid source of cookbooks before continuing
        #
        @install_path = config[:cookbook_path].first
        ui.info "Installing #@cookbook_name to #{@install_path}"

        @repo = CookbookSCMRepo.new(@install_path, ui, config)
        #cookbook_path = File.join(vendor_path, name_args[0])
        upstream_file = File.join(@install_path, "#{@cookbook_name}.tar.gz")

        @repo.sanity_check
        @repo.reset_to_default_state
        @repo.prepare_to_import(@cookbook_name)

        downloader = download_cookbook_to(upstream_file)
        clear_existing_files(File.join(@install_path, @cookbook_name))
        extract_cookbook(upstream_file, @install_path)

        # TODO: it'd be better to store these outside the cookbook repo and
        # keep them around, e.g., in ~/Library/Caches on OS X.
        ui.info("removing downloaded tarball")
        shell_out!("rm #{upstream_file}", :cwd => vendor_path)

        if @repo.finalize_updates_to(@cookbook_name, downloader.version)
          @repo.reset_to_default_state
          @repo.merge_updates_from(@cookbook_name, downloader.version)
        else
          @repo.reset_to_default_state
        end


        unless config[:no_deps]
          md = Chef::Cookbook::Metadata.new
          md.from_file(File.join(@install_path, @cookbook_name, "metadata.rb"))
          md.dependencies.each do |cookbook, version_list|
            # Doesn't do versions.. yet
            nv = self.class.new
            nv.config = config
            nv.name_args = [ cookbook ]
            nv.run
          end
        end
      end