anchor.diff:          _ -> {error, file_exists}
       end.
   
  --spec concatenate(file:filename(), file:filename()) -> 'ok' | {'error', term()}.
  +-spec concatenate(file:filename(), file:filename()) -> ok | {error, term()}.
   concatenate(Src, Dst) ->
       {ok, SrcIO} = prim_file:open(Src, [read, raw, binary]),
       {ok, DstIO} = prim_file:open(Dst, [append, raw]),
  
positive.code:     Local = filename:join(Root, Path),
      {ok, Local, Url}.
  
  -spec parse_url(binary() | string()) ->
          'not_ddfs' | {host(), volume_name(), object_type(), string(), object_name()}.
  parse_url(Url) when is_binary(Url) ->
      parse_url(binary_to_list(Url));
  parse_url(Url) when is_list(Url) ->
  
negative.code:             Error
      end.
  
  -spec diskspace(nonempty_string()) -> {error, invalid_output | invalid_path} |
                                        {ok, diskinfo()}.
  diskspace(Path) ->
      case lists:reverse(string:tokens(os:cmd(["df -k ", Path]), "\n\t ")) of
          [_, _, Free, Used|_] ->
  