Spy on your users through SSH

You just connected through SSH and are wondering what your users are doing. Do a

cat /dev/vcs1

and this will show you what happens on the first console. If someone is typing, you’ll be able to get an output of his keystrokes. Substitute cat /dev/vcs1 with cat /dev/vcs2 or cat /dev/vcs3 and so on for other consoles.