Assuming you were actually going to use something like this, you're likely using full disk encryption. At that point, the better option would be (IMO) to simpl

Assuming you were actually going to use something like this, you're likely using full disk encryption. At that point, the better option would be (IMO) to simply blow away the first 2 MB or so of your disk (where the LUKS master key is stored), run a "sync", and execute an immediate "reboot -f" (along with, perhaps, the other options that skip spitting out the warning message, writing an entry to utmp/wtmp or whatever, and so on). There wouldn't be a real need to actually zero/wipe the entire drive (which would take a bit, even at SSD speeds).