dd if=/dev/urandom /dev/sda bs=512 count=1 conv=notrunc
This was helpful for me, but I had to add of=
dd if=/dev/urandom of=/dev/sda bs=512 count=1 conv=notrunc
I intend to protect users from inadvertently wiping disks with:
read -r -p "Are you sure? [y/N] " response
response=${response,,} # tolower
if [[ "$response" =~ ^(yes|y)$ ]]