While that might be the case (that the author is non-technical) you could also argue that the wording "shouting commands [at the dog] ... in Unix" has a nicer flow to it -- than "shouting Unix commands [at the dog]"

The first starts off as a perfectly normal sentence: "he shouted commands" and then ends with a funny surprise: "in Unix!" The second doesn't quite have the same punch. So if you want to favor the writing instead of the tech, even if you're a technical person, you might word it like the author did.