That, however, is an extremely well-known class of bug. The post is about an extremely obscure (but presumably quite common at the time!) class of bug.
Also, if you're writing about bug x, you might make a minimal reconstruction of that piece of code only to showcase bug x, instead of the full version with all bells and whistles.
That's usually prevented by using double dashes ("--") to indicate the end of options, before the file argument. I try to remember to include include double dashes in my shell scripts for as many commands as possible (it's easier to just include them rather than figure out whether a user could possible influence the filename).
if tarball or path is user input then they could be used to inject tar command options.