Knife for cutting steak slices from whole ribeye?
You will need a standard curved 10" butcher knife. You cannot cut a proper steak with a straight-bladed chef's knife, as the blade will not contact the cutting board at the proper angle. The knife needs to be sharp. A sharp knife is less likely to cut you than a dull one because the handler will not have to fight with it. Also, please observe all safety regulations and common sense when using a dangerous instrument like a butcher knife.

Here is an image of  standard curved 10" butcher knife:  



(Source)