Dangerous Commands In Linux WHICH SHOULDNT BE USED

I read this announcement on the ubuntu forums, I happened to see it only a few days back, the announcement is VERY IMPORTANT, Its regarding certain commands which SHOULD NOT BE USED at any case in the terminal.NEVER EVER RUN ANY COMMAND UNLESS YOU ARE SURE OF WHAT IT DOES.Here is this link PLEASE READ IT CAREFULLY AND DO NOT TRY IT.