Should a 2 week old baby be sleeping all night 6 hours or longer?

If your lucky. Some infants will develop a feeding pattern that follows the normal wake sleep pattern their mother had in pregnancy.If they are feeding effectively during the day and gaining appropriate weight it is fine, especially for the larger babies.If a baby is tiny, 5-6 lb, I want them wakened to feed at night. After they get close to 8 lb I worry less about their feeding cycles.
Sleep. Yes, some babies are able to sleep through 6 hours at night.
Need more info. You need to ask your pediatrician that question. All infants are different and there is no cookie cutter answer. He/she knows your infant better than me.