beep 1.3-4+deb9u1 (armhf binary) in ubuntu bionic

 beep does what you'd expect: it beeps. But unlike printf "\a" 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.