Yelp has a 3 step interview process. Luckily for me I was able to get through only 2 of those steps. In the first step a Yelp recruiter called me and asked me some basic CS and logic questions like how many bits and a byte and such and some Linux related questions already mentioned here. Then the second step is a Skype interview with a Yelp software engineering and they decide if you are good enough for onsite interviews which is the 3rd step. Sadly I was not picked for the 3rd step.

Leetcode style interview online via link, then a 1 on 1 technical interview with a lead developer also online where you can ask questions about the role and working at yelp, later more in depth technical tests and finally references and psicological tests.