Can anyone without shell/cli knowledge really be called an experienced user?
PS: This actually makes me think interesting thoughts about the meaning of the word 'user', the many different senses in which we use it, and the many overlapping ways one could be said to be an experienced user, such that many experienced users all have entirely distinct skill sets with no overlap.
I'd recommend either O'Reilly's bash shell book or 'classic shell scripting' which covers a bit more than just a shell like bash.