Disk eraser script

dangerous_erase.sh

#!/bin/bash
# From http://unix.stackexchange.com/questions/72216/fast-way-to-randomize-hd
DISK="/dev/sda"
SIZE=`fdisk -l | grep "${DISK}" | awk '{print $5}'`

echo "Erasing ${DISK} (size ${SIZE} bytes)"
read -p "Are you sure? " -n 1 -r
echo    # (optional) move to a new line
if [[ $REPLY =~ ^[Yy]$ ]]
then
  echo "OOOh!"
  openssl enc -aes-256-ctr -pass pass:"$(dd if=/dev/urandom bs=128 count=1 2>/dev/null | base64)" -nosalt </dev/zero \
   | pv --progress --eta --rate --bytes --size ${SIZE} \
   | dd of=${DISK} bs=2M
fi