> since undergrads trying to hack their grade higher

Would student records even be stored on an unix system at the time? I am under the impression that Unix was very much a research operating system in the 1970's (either the subject of or a tool for). Administrative functions were more likely to be conducted with an IBM mainframe. (At least that is how it was when I arrived at university a couple of decades later, which I always took to be a legacy thing.)