A Unix programmer needs three main languages in his toolbox: Shell, Python and C. I recommend beginners learn them in that order.
The best book I've seen on shell scripting is by Arthur & Burns:
Unix Shell Programming. Save money, buy yourself a used copy.
The official
Python website has a good online tutorial, along with other references and book recommendations.
There are Qt and Gtk bindings for Python, and I recommend beginners use them rather than struggle with the C++ interfaces.
I no longer recommend C++ or Java for anything. But you'll need them if you're going to be hacking on other people's code. (I'm not a web programmer, and don't know if people are still using Javascript for that kind of thing. But you said you wanted to be a *Unix* programmer.)
Since this is a thread about minimalism, it's hard to recommend Perl rather than Python.
You certainly don't need both. But again, you might eventually pick up some Perl in order to hack on someone else's code. Otherwise, don't bother.
Assembly is the coolest thing ever and I love it. But save it for much much later when you know what you're doing and why.
I have never recommended Forth (never learned it either.) You'll probably never need it, since it's only found in little niches well off the beaten track. Haskell and Occam are the same way. Don't misunderstand me: they're all fine languages with some excellent points in their favor. It's just that very few people use them, and a beginner is better advised to spend his time learning some of the more mainstream languages.