It is customary to remain awake throughout the night of Shabuot and immerse oneself in Torah study. According to Sephardic practice, one who remains awake the entire night does not wash Netilat Yadayim with a Beracha the next morning. One may thus continue learning even after Amud Ha’shahar (daybreak) on Shabuot morning, and one does not have to stop to wash his hands. There is no requirement to interrupt one’s learning to wash his hands at Amud Ha’shahar. However, it is proper to stop at Amud Ha’shahar to recite Birkat Ha’Torah. According to some authorities, the recitation of Birkat Ha’Torah in the morning covers a person’s Torah study only until Amud Ha’shahar the next morning, even if he does not go to sleep. Therefore, those who remain awake throughout the night on Shabuot should stop at Amud Ha’shahar to recite Birkat Ha’Torah, and then return to their studies.
One should recite Keri’at Shema Al Ha’mita – the bedtime Shema – even if he remains awake all night. Therefore, on Shabuot night, one should ensure to recite the bedtime Shema before Hasot (midnight as defined by Halacha). Our custom in any event is not to recite the Beracha of "Ha’mapil" on any night, but the rest of the text of Keri’at Shema Al Ha’mita should be recited before Hasot even on the night of Shabuot.
Summary: One who remains awake on Shabuot night should nevertheless recite Keri’at Shema Al Ha’mita before Hasot, without the Beracha of "Ha’mapil" (which in any event is never recited according to our custom). At Amud Ha’shahar, one should stop to recite Birkat Ha’Torah. One does not have to wash Netilat Yadayim at Amud Ha’shahar.
