There must be hundreds of restaurants in Cairo situated on the banks of the Nile River.
Actually, I can’t be sure of the number given that I didn’t walk the whole route. I’m extrapolating form the few kilometres I did walk, in which there were dozens of places to eat, from high end establishments catering to tourists and expatriates to low budget chains to Egyptian food. Something for every taste, and every price range. Day and evening.
While you eat you can watch the boats going up and down the river. Commercial traffic by day, and a lot of boat parties after dark, complete with loud music.
Next time you are in the city, put sitting by the Nile on your list of must-do activities.