Easter eggs in tools or funny tools [closed]

Question

I always install the sl program that produces an ASCII train when you misspelled ls on the command line. It makes me laugh from time to time. There's also the supercow powers of apt or the offensive sudo messages.

Now that I recall, for instance, tar refuses cowardly to create an empty file.

What other funny tools or easter eggs have you found as a sysadmin?

Answer 1

figlet to make beautiful or funny motds or funny console displays.

$figlet "Figlet"

 _____ _       _      _   
|  ___(_) __ _| | ___| |_ 
| |_  | |/ _` | |/ _ \ __|
|  _| | | (_| | |  __/ |_ 
|_|   |_|\__, |_|\___|\__|
         |___/

cowsay and cowthink display what you want in a funny (also trashy) cow ! Try the -f ghostbusters.

$cowsay "serverfault.com"

 _________________ 
< serverfault.com >
 ----------------- 
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

Answer 2

You should also see if aptitude has supercow powers.

Answer 3

The vigor assistant