Commands that actually do something
Click the black area first, otherwise your keystrokes go nowhere. Then type. It takes help, ls, cd, cat, tree, pwd, whoami, uname, date, echo, history, clear, sudo and search. Tab completes a filename if there is only one candidate. Up arrow walks back through what you typed.
Search prints results as numbered text with the address underneath, which is what a results page looks like once you strip the layout off it.
The sudo joke
Everyone tries it. You get told you are not in the sudoers file and that the incident has been reported, which is exactly what a real Unix box says, and the reason the joke works at all is that half the people typing it have seen that message for real.
It is not a shell
Nothing here touches your machine. There is no server on the other end. The filesystem is four folders that exist only in the page, and closing the tab deletes the lot.
If you want the other end of the spectrum, google in 1998 keeps the layout and throws away the last twenty five years of design instead. The google matrix page drops text down the screen without asking you for anything.
