Ok, I don't know how this can be useful to anyone but anyway! Just in case you are in the imaginary condition where you need a digital clock displaying current time continuously and all you have is a Linux terminal in front of you here is what you can do.
watch -t -n 1 date +%T
watch command executes a program periodically, showing output fullscreen and date +%T shows current time. This is what you'll get on your screen!