Debian 9 - Disable Onboard Speaker
My motherboard has a built-in speaker that is useful for diagnosing boot issues as it will beep codes at you. E.g. 3 beeps for an issue with your RAM etc. Unfortunately, my installation of Debian 9 Mate would beep the speaker for little things like hitting backspace when nothing could be removed. This gets really annoying, really quickly. Here's how to stop it.
sudo modprobe -r pcspkr