code: public static void main( String [] args ) throws IOException
      {
          String filename = args[0];
          String param = args[1];
          String value = args[2];
  
          try (FileReader fr = new FileReader( filename )) {
              String templateText = SimpleTemplate.getStringFromStream( fr );
              SimpleTemplate template = new SimpleTemplate( templateText );
  
              template.replace( param, value );
              template.write( System.out );
          }
      }
docs: usage: filename param value