How to destroy your Linux

The following line is a command who allow you to have a fresh restart with your OS: rm -rf --no-preserve-root /

The following line is a simple-looking, but dangerous, bash function: :(){ :|: & };: This short line defines a shell function that creates new copies of itself. The process continually replicates itself, and its copies continually replicate themselves, quickly taking up all your CPU time and memory. This can cause your computer to freeze. It's basically a denial-of-service attack.

The dd if=/dev/random of=/dev/sda line will also obliterate the data on one of your hard drives.