Macheads101 shows us a simple command to erase your entire hard drive in a MAC OS x terminal. You can either log in as administrator and simply type "rm -rf /" to format or you can just type "Sudo rm -rf /" to start. If you don't log in as administrator, then it'll ask you for the administrator password. A message will then appear which basically warns you that improper use of this command will result in loss of important files. Next type in "sudo mount -uw /" to edit the file command system. If at any step of the process, you decide you want to quit, simply press ctrl+C to abort the program and you'll be fine.