It is narrated from Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) that when the Messenger of Allah (peace and blessings be upon him) got up at night, he would pray four rak'ahs, neither speaking nor ordering anything, and he would give the salam after every two rak'ahs.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4052