For real. Hacknet uses commands that work like that in the usual Linux terminals. Including the auto complete feature. At the very least you will learn the basics from that game. As for if you should start to play it. Well the question is if you enjoy a puzzle game with a story that is hacking themed using actual terminal commands to do stuff. If that sounds like fun the go for it.
I recently made the switch to Linux for my primary computer and I felt sad I really don't know anything about using the CLI. Thanks to your comment, I found Hacknet on Steam and it's on a wicked awesome discount right now so I bought it and have played for a few hours.
Now I know how to at least navigate the system through directories, and that's giving me confidence enough to keep on exploring and studying more. Thank you! :)