substring ‘;’ STRING ‘;’ START ( ‘;’ END )? | bnd
Description: static String _substring = "${substring;<string>;<start>[;<end>]}";

- # substring ';' STRING ';' START ( ';' END )?

      static String	_substring	= "${substring;<string>;<start>[;<end>]}";

      public String _substring(String args[]) throws Exception {
      	verifyCommand(args, _substring, null, 3, 4);

      	String string = args[1];
      	int start = Integer.parseInt(args[2].equals("") ? "0" : args[2]);
      	int end = string.length();

      	if (args.length > 3) {
      		end = Integer.parseInt(args[3]);
      		if (end < 0)
      			end = string.length() + end;
      	}

      	if (start < 0)
      		start = string.length() + start;

      	if ( start > end ) {
      		int t = start;
      		start = end;
      		end = t;
      	}

      	return string.substring(start, end);
      }