checks if there were no errors doing dd to a block device

ddCheck.sh

#!/bin/sh
usage="$(basename "$0") [-h] [-i path] [-o path]
md5sum comparison of .img and a block device.

where:
    -h  show this help text
    -i  path to .img (i.e. /home/debian.img)
    -o  path to blk device  (i.e. /dev/sda etc.)
"

while getopts ':hi:o:' option; do
    case "${option}" in
        h)
            echo "$usage"
            exit
            ;;
        i)
            inPath=$OPTARG
            ;;
        o)
            outPath=$OPTARG
            ;;
        :)
            printf "missing argument for -%s\n" "$OPTARG" >&2
            echo "$usage" >&2
            exit 1
            ;;
        \?)
            printf "illegal option: -%s\n" "$OPTARG" >&2
            echo "$usage" >&2
            exit 1
            ;;
    esac
done

if [ "$#" -lt 4 ]
then
    echo "Not enough argumnets" >&2
    echo "$usage" >&2
    exit 1
fi

#status=none
md5blk=$(sudo -k dd status=none if=$outPath bs=512 count=$((`stat -c%s $inPath`/512)) | md5sum | awk '{print $1}')
md5img=$(dd status=none if=$inPath bs=512 count=$((`stat -c%s $inPath`/512)) | md5sum | awk '{print $1}')

echo "blk: " $md5blk
echo "img: " $md5img

if [ "$md5blk" = "$md5img" ]; then
    echo "Match"
else
    echo "Error, no match!"
fi