Install beep by entering the following commands in the terminal:
sudo apt update sudo apt install beep
advanced pc-speaker beeper
beep does what you'd expect: it beeps. But unlike printf "" beep allows you to control pitch, duration, and repetitions. Its job is to live inside shell/perl scripts and allow more granularity than one has otherwise. It is controlled completely through command line options. It's not supposed to be complex, and it isn't - but it makes system monitoring (or whatever else it gets hacked into) much more informative.