The degree of realism should
not in any case impact your game depth. Fantasy games can be really deep, realistic games can be flat as a pancake.
You are probably right about the approachability, though. But then again, commands would have to be learned either way. In addition to that, games that teach you something are highly valuable. The art lies in making that process fun.
To tackle your dilemma, I think, simple unix commands such as ls or cp should totally be fine. You could still have "shell scripts" like "magickHackerTrick" or your "nodes" command to have more speakable names and not require any player to become a linux crack first before playing your game.
The opposite is actually the case here. Players that are used to work on linux systems will find a much quicker entrance to your game as they already know how things work and don't have to learn new fantasy commands first. Non-skilled players will get an advantage
after playing your game as they will take real life knowledge out of it. Heck, you could even advertise in that manner.
I would suggest, maybe implementing some smaller algorithm to detect players' precognitions. If the first thing a player does is to get a directory listing followed by finding out on what OS they are, you can be pretty sure they know where they're at. You might even skip some basic tutorials. And if they don't, teach'em! And be sure to reward them with an acknowledging sound effect to provide a sense of accomplishment here.
Of course that's only my opinion. But I'm pretty sure, you can create a simple, realistic and compelling experience.
