Read up on the Penal Code first and foremost.

Absolutely illegal in CA PC 12020(a)(1): any ballistic knife, belt buckle knife, lipstick case knife, cane knife, air gauge knife and pen knife.

PC 653k: cannot carry any "switchblade" knife with a blade longer than two inches. "Switchblade" covers everything from spring loaded to being able to open it with a flick of your wrist.

PC 12020 also says you cannot carry concealed a dirk or dagger.

Knives have even become common in CA and most of us coppers don't bat an eyelash when a law-abiding citizen is carrying one. We mostly use these laws to get those not so law-abiding citizens. There are however always exceptions so CYA.