I pressed some key combination and got a big full screen black terminal screen with a login prompt.After logging in, I tried startx to get the UI back, but got a messageFatal server error:Server is already active for display 0If this server is no longer running, remove /tmp/.X0-lock and start again.So - what did I do to get me the black prompt in the first place, and how do I get back to X?
How do I get back to X?
gnome;terminal
You pressed Ctrl+Alt+Fn for some n, and you need to press Alt+F7 (usually) to get back.