tzs' solution is clever, but if you're planning to simply toss a bad drive (and don't particularly care which blocks are bad), something like tee /dev/the/disk

tzs' solution is clever, but if you're planning to simply toss a bad drive (and don't particularly care which blocks are bad), something like tee /dev/the/disk </dev/urandom | sha256sum and sha256sum /dev/the/disk should also work fine.