If I read the manual for everything I've ever used, I'm not sure I'd have time to actually accomplish anything in the end.
Sure, let me spend a day reading through the lists of keyboard/mouse shortcuts for every piece of software I use just to see if there's anything useful in there? No thanks...
Good UX would pop up a balloon informing me of the feature after the first time I held down my left-arrow key for more than, say, keypresses.
CLIs are like that. On the bright side, things rarely change. So the stuff you read in the manual 30 years ago still likely works. I prefer it over relearning GUIs with every update.
Of course, you might as well disregard the manual and discover things on your own as you need them. Nevertheless, it helps to go at this with a mindset of "this feature surely already exists" lest you're compelled to develop a worse version of the feature yourself.
While technically true, I tend to forget what I read after some time, especially tips and tricks that did not seem that
useful when I first read them. So RTFM is not the silver bullet unless you somehow have a system that reminds you to re-read every manual every x months.
