Landlords rights

What are a landlord’s rights? I don’t know what rights they have exactly it seems that the character Michael Keaton was playing basically pulled a squatter move and just took up the space with no real agreement and the landlords has pretty much no rights. It seems like total B.S. I don’t know what they were thinking. The second I found out he was in there and we had no signed agreement I would have called the cops and had him removed immediately. I thought people in San Francisco were smarter than that. I don’t know if this is accurate but it seemed like when the cop or the lawyer told them that now that he is in there he is their tenant and their problem? He is clearly breaking some law. I don’t know I too much about the law as a landlord. I have rented pretty much all y life and I like to think of myself a good renter and I never really have an issue to take up with the owners. I don’t know if the film we watched was before or after the whole squatters right stuff that went down. I cant really remember when it happened or what it was really about but I remember a lot of east bay punk and hardcore bands talking about it and how the lazy squatters need to get jobs and stop making S.F a slum or something like that. I don’t really like punk, I was raised on death metal. My mother has been in the real estate business for a long time maybe I should ask her. But about the film I sure they had to be more that they could have done to get Michael Keaton’s character out. It’s funny because when he got angry at his partner he sounded like Beetlejuice.