Quite good introductory book for beginners, found a couple of points on common commands that I actually wasn't aware of in there as well - despite being a Linux engineer for several years - always something new to learn.
Could use a bit better editing, however the point was still obvious where that was the case (though I did chuckle at 'dpkg' being referred to as 'dkpg' in one line).
Other than that, the only issue would be that it is getting a little dated and missing a few small things (like the introduction of dnf on rpm-based systems, for example), but that kind of thing is expected with IT books as they age.