Somebody has a code or library?
Code? What about the TimeCheck example that you posted right above that line. Is that giving you trouble?
I don't know how can I get the shield to recieve the current date and time.
The idea of that TimeCheck sample sketch is that it asks the Linux side of the Yun for the time.
The Linux side gets the time and date from the Internet by periodically contacting an NTP server. Therefore, your Yun must have Internet access. If it does, it should all be automatic. (Although it may take a minute or two after the Linux side boots before the time is valid.)
So after the shield get the time I have to give it somehow to the clock.
So, use the TimeCheck example as a guide. Once you read the time from the Linux system into your sketch, it's up to your code in the sketch to do something useful with that time (like display it.)
I'm not sure what exactly is your problem here. Which part are you having trouble with?