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);
}