Luckily, my older brother had brought home a "Learning UNIX" book when I was a kid, which helped me learn about UNIX fundamentals years before getting my hands on a machine with it. I was fascinated with the book because UNIX sounded too advanced compared to what I was using back then (an 8-bit Amstrad CPC464). I still use the same knowledge such as managing shell background jobs, exiting vi, using tar, permissions, and so forth 30 years later. UNIX is quite magical in its consistency.