sudo rm -r / --no-preserve-root

The command in GNU/Linux (or maybe other Unix-based operating systems) that deletes the root directory (/). Some trolls from the internet tell new users to run this command, saying that it will do insert something good here to your system.

If you have ever stumbled upon a person on the internet telling you to enter the command "sudo rm -r / --no-preserve-root", don't do it. Only do it if you know what you're doing, it will delete the system and all of your data.