Hardware hotplug events on Linux, the gory details

One day, I suddenly wondered how to detect when a USB device is plugged or unplugged from a computer running Linux. For most users, this would be solved by relying on libusb. However, the use case I was investigating might not actually want to do so, and so this led me down a poorly-documented rabbit hole. ↫ ArcaneNibble (or R) And ArcaneNibble (or R) is taking you down with them.