Questions & Answers about الكل بيعرف القانون.
Here الكل means everyone / everybody. Literally, it is something like the all, but in natural Levantine it is a very common way to say everyone.
A close alternative is كل الناس, also meaning everyone / all the people.
Because الكل is usually treated as a singular collective in everyday Levantine. So speakers normally say الكل بيعرف rather than الكل بيعرفوا.
In other words, the meaning is plural, but the grammar is usually singular.
In Levantine Arabic, بـ usually marks the ordinary present or habitual form. So بيعرف means he knows or he generally knows, depending on context.
This is one of the clearest signs that the sentence is colloquial. In Standard Arabic, you would normally have يعرف without بـ.
Arabic verbs already contain information about the subject. The form بيعرف by itself points to third-person masculine singular.
Since the subject الكل is already stated, there is no need to add a separate pronoun.