Make noise on Ubuntu 18.04 without internet

I have an Ubuntu machine that currently has no internet connection. I want to set it up so it makes a sound when internet comes back. I'm not sure this machine has a PC speaker, but there is a speaker connected to the on-board sound card. In the past I think I used cat /dev/urandom > /dev/audio for this, but this doesn't seem to work anymore. None of these tools are currently installed: beep, aplay, padsp None of these made any sound: modprobe pcspkr echo -e '\a' > /dev/tty1 echo -e '\a' > /dev/console This failed with write error: File descriptor in bad state: cat /dev/urandom > /dev/snd/pcmC0D0p