Is it possible to access to the framebuffer in order to put a pixel on the screen from the command line?

I am not sure if it is the only possible way, but I read that in order to put a single pixel onto the screen at a location of your choice one has to write something into a place called framebuffer. So I became curious, if it is possible to enter into this place and write something into it in order to display a single pixel somewhere on the screen.