The book is called "Advanced Linux Programming" and starts with a chapter that does a Hello World in C. Somehow, I feel like there's a bit of a disconnect.
I guess it's advanced in the sense of "not beginner". A typical beginner book might start with ls, cp, and nano and get to hello world around the midpoint.
Advanced Linux Programming is just C programming!
Joke aside, you are right 'Hello World' does seem disconnected from 'Advanced'