It's tough to for me to judge cause I've been programming for 30 years maybe I'm underestimating how hard it is, but I look at learning a new language very different that trying to understand the graduate level CS work I've seen at a top STEM school.
Git, shell, basics.. even simple python if you have any at all programming experience - not nearly as hard as what they're teaching in the class.
Most of the time something like that like learning latex or git basics.. they'll say.. you'll pick up what you need. They're not gonna spend 12 weeks on those subjects they aren't hard enough.
Discrete tools are fairly easy. On the other hand, I think a lot of people here would laugh at the "text book" for the introductory FORTRAN course I took at said school.
Of course, you were struggling with fairly primitive tools at the time as well. Made a typo? Time to beg the grad students running the facility for some more compute cycles.
Although it's out of print I don't immediately see a full copy online. https://www2.seas.gwu.edu/~kaufman1/FortranColoringBook/Colo...