I just want to point out that there are 3 different topics you're talking about there:
- Development/building on Linux
Indeed, there are pretty deep concepts behind each of them: C++ is related to fundamental programming concepts, object orientation, and metaprogramming, OpenGL deals with framebuffer rendering/graphics, and Linux development deals with source control, Makefiles, compilers, and configuration setups.
These concepts are not orthogonal by any stretch of the imagination, but it might help to keep in mind that each of them can be studied without the other.
Speaking from personal experience as a 'graphics guy', I would suggest you look further than OpenGL if you want to learn C++. OpenGL is great, don't get me wrong, but it is just an API, and a fairly limited one at that. You won't learn much C++ trying to figure out how to set up texture contexts and binding VBOs.
I would recommend writing a raytracer or your down software-based rasterizing renderer (or both!) - you'll find youself diving right into the data structures that are important to graphics and tackling 'fundamental' problems that really test your programming abilities, versus realizing that you passed GL_LINE to glBegin() instead of GL_LINES or some stupid API issue like that.
Later, you can work on your OpenGL skills; heck, you could even play with it in Python if you're curious. You'll find that any API is easier and more satisfying to use if you say 'How does this API address the following problem in graphics?' as opposed to browsing through the API reference and saying 'Ooh, what does this function do?'.
As for the Linux part, my advice would be to read up on Makefiles and spend some time writing them for various projects. When you've really got a handle on them, you can move on to CMake or autotools or whatever - but jumping into those without knowing that basic mechanism does you a disservice. I'd also recommend experimenting with one of those fancy programming editor (I recommend The One With All of the Modifier Keys), but there are several that are very good.