[lkozma]

Others have put it more eloquently already but I can just suggest the same: start working on a project and pick up what you need as you go. If you want to learn Linux, do something that involves some server side work: get some cheap web hosting account (or one almost for free on nearlyfreespeech as long as you don't have traffic) and start compiling programs from source, set up mod_rewrite, etc. etc. etc. Otherwise get a cheap computer, install Linux and configure everything as you want, hunting for answers on forums. By the time you are done, you will know more about Linux than most self-proclaimed experts.

Don't think about algorithms, data structures and all other topics as some huge roadblock, they really contain a lot of loosely connected topics which are not all that difficult if you look at them one at a time with enough patience. "What One Fool Can Do, Another Can Too". You get more out of reading a textbook when you already know disconnected bits and pieces and you want a more unified view.

Your writing reminds a bit of my friend who is the best guitarist I know, but has a constant inferiority complex, because he says he "doesn't know music theory". I don't know much about music, but if I try to get down to the specifics of what he doesn't know, it turns out that he actually knows a huge amount, but he still keeps repeating "if only I knew some music theory"...