ctrl-h
Apparently WordPress will not let me post a thing that short, so here’s the why: the internet is full of fluff, and that’s fine, but oftentimes you just want to find something quick. I was looking for this answer and was instantly annoyed by the first thing I clicked, which took two pages worth of content and graphics to explain what hidden files are, why you may want to see them, etc etc etc. So here it is. ctrl-h.