The imperative with a subject

We can mention the subject you when it contrasts with another person.

I'll wait here. You go round the back.

You can also make an order emphatic or even aggressive.

You be careful what you're saying.

 

NOTE

A few other phrases can be the subject.

All of you sit down! Everyone stop what you're doing.

The negative don't comes before the subject. Don't you talk to me like that.