As far as programming for text-based programs versus graphical programs, the
language is the same. What has been said in your previous thread is that in order to code graphical programs you need to use
third-party libraries.
When we say Windows Programming, we usually mean graphical programs; however, you can write text-based programs on Windows as well.
It is the same for Linux: text-based programming doesn't require third-party libraries; however, graphical programming requires third-party libraries.
In interacting with the operating system, you'll find that Windows and Linux can be very different, but again, the language is not different.
Just take your time, and learn C++ first, and concentrate on text-based programs to begin. Here is a list of very good practice programs:
http://www.cplusplus.com/forum/articles/12974/.
After you master some of these, then look at writing some GUI code!
Good luck!