# File lib/chef/knife/cookbook_bulk_delete.rb, line 35
      def run
        unless regex_str = @name_args.first
          ui.fatal("You must supply a regular expression to match the results against")
          exit 42
        end

        regex = Regexp.new(regex_str)

        all_cookbooks = Chef::CookbookVersion.list
        cookbooks_names = all_cookbooks.keys.grep(regex)
        cookbooks_to_delete = cookbooks_names.inject({}) { |hash, name| hash[name] = all_cookbooks[name];hash }
        ui.msg "All versions of the following cookbooks will be deleted:"
        ui.msg ""
        ui.msg ui.list(cookbooks_to_delete.keys.sort, :columns_down)
        ui.msg ""

        unless config[:yes]
          ui.confirm("Do you really want to delete these cookbooks? (Y/N) ", false)

          if config[:purge]
            ui.msg("Files that are common to multiple cookbooks are shared, so purging the files may break other cookbooks.")
            ui.confirm("Are you sure you want to purge files instead of just deleting the cookbooks")
          end
          ui.msg ""
        end


        cookbooks_names.each do |cookbook_name|
          versions = rest.get_rest("cookbooks/#{cookbook_name}")[cookbook_name]["versions"].map {|v| v["version"]}.flatten
          versions.each do |version|
            object = rest.delete_rest("cookbooks/#{cookbook_name}/#{version}#{config[:purge] ? "?purge=true" : ""}")
            ui.info("Deleted cookbook  #{cookbook_name.ljust(25)} [#{version}]")
          end
        end
      end