public static String reader(File f, String field) {
		String content = "null";
		try {
			FileReader fr = new FileReader(f);
			BufferedReader br = new BufferedReader(fr);
			String line = null;
			while ((line = br.readLine()) != null) {
				if (line.startsWith(field)) {
					content = line.replaceAll(field + ":", "");
					break;
				}
			}
			//رļ
			br.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return content;
	}