corruption_detector.sh

#!/bin/bash

input=$1
hole_size=$2
hole_found=false
old_line=
sample=
previous_offset=
if [ "$hole_size" = "" ]; then
    hole_size="1024"
fi

FILESIZE=$(stat -c%s "$1")
echo "Size of $1 = $FILESIZE bytes."

hexdump $input | while IFS= read -r line
    do
        if [ "$hole_found" = true ]; then
            offset=$(echo "$line" | awk '{ print toupper($1) }')
            count=$(echo "ibase=16; $offset - $previous_offset" | bc)
            cond=$(echo "$count >= $hole_size" | bc)

            if [ "$cond" = "1" ]; then
                echo "Found hole of size "$count" at 0x"$previous_offset", sample: "$sample""
            fi
            hole_found=false
        fi

        if [ "$line" == "*" ]; then
            previous_offset=$(echo "$old_line" | awk '{ print toupper($1) }')
            hole_found=true
            sample=$old_line
        fi
        old_line=$line
    done