A method of managing data contained in a file includes extracting locality information contained in a printing data file; determining whether the same locality information exists between the extracted locality information and input locality information; and analyzing printing data contained in the printing data file if it is determined that the same locality information exists. A method of managing data contained in a document includes extracting locality information by reading a document; determining whether the same locality information exists between the extracted locality information and input locality information; and duplicating information contained in the document if it is determined that the same locality information exists.