#!/bin/sh

# ./badb.sh /dev/sdd 0.9
# starts from 90th% block of the device using 4k blocks.

DEV=$(basename $1)
BLOCKS=$(cat /proc/partitions| grep $DEV| awk 'NR==1{ print $3 } ')
SIZE=1024
NB=4
BSIZE=$(( SIZE * NB ))

echo "total 1k blocks: $BLOCKS"
BLOCKS=$(( BLOCKS / NB - 1 ))
echo "total ${NB}k blocks: $BLOCKS"

START=0
if [ -n $2 ]; then
    START=$(echo "$BLOCKS * $2"| bc)
    START=$(printf "%.0f" $START )
fi
echo "start block: $START"

sudo umount ${1}1 || true
sudo badblocks -nsv -b $BSIZE  -p 1 -c 32768 -o badblocks-$DEV.txt $1 $BLOCKS $START