    # 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