When developing in Ubuntu, very often a command may take so long that I stop staring at the terminal anymore. It would be pretty sweet if there is a way to alert me when the job is done, while me is reading a book or doing something else.

First thing to do is to turn the motherboard speaker on.

sudo modprobe pcspkr

Then, one is free to play with the beep command.

sudo apt-get install beep

Now you are good to go.

anyCommandYouWant; beep