Brightlight, "Don't you lie!" means the same thing as "Don't tell a lie!". Maybe MrVacBob was wondering whether 「ウソをつくんじゃねぇ！！」 means 「嘘を吐くな」 or 「嘘を吐かない」.
"Don't you lie!" has a sort of nonstandard feel to it. But it does mean "Don't lie!" or "Don't tell a lie!" Perhaps English speakers will more readily recognize an example like "Don't you take that tone with me!" (which is a variant of "Don't take that tone with me!".
In the English imperative, the subject is usually omitted, but it doesn't have to be. In the case that it's not, there's a reversal of subject and verb, similar to in questions.
"You go now", declarative form, becomes "Do you go now?" (splitting "do go", but still with the reversal) or the more old-fashioned but more direct "Go you now?" in the interrogative form. In the imperative, "Go you now!". Perhaps more recognizable in the Shakespearean commonplace "Hie thee hence!" or whatever (not any particular quote, it just popped into my head as an example).
