public void search(File file) throws IOException
   {
      Scanner in = new Scanner(new FileInputStream(file));
      int lineNumber = 0;
      while (in.hasNextLine())
      {
         lineNumber++;
         String line = in.nextLine();
         if (line.contains(keyword)) System.out.printf("%s:%d:%s%n", file.getPath(), lineNumber,
               line);
      }
      in.close();
   }