This article should be named "Learn just enough Unix to get things done". Almost everything explained can be done on any Unix-like system like macOS and it's not exclusive to Linux.
It could be mentioned early in the article.
However for its target audience (I assume) that would be far less useful.
("This looks great but seems to be about Unix and I know this is a Linux thing.")
And you can get quite a bit done on Linux without knowing any of it.