Bash script to automatically find and fix the partitions in an image file on linux using losetup, fdisk, mke2fs and fsck.

fix-img-parts.sh

#!/bin/bash
#
# This image will fix all of the partitions in a disk image.
#
# Usage:
#   fix-image.sh test.img
#
# License: MIT Open Source
# Copyright (c) 2016 by Joe Linoff

# ================================================================
# Main
# ================================================================
ImgFile="$1"
echo "INFO: ImgFile=$ImgFile"
if (( ${#ImgFile} == 0 )) ; then
    echo "ERROR: Must specify an image file."
    exit 1
fi
if [ ! -f "$ImgFile" ] ; then
    echo "ERROR: File does not exist: $ImgFile."
    exit 1
fi

# Try to fix all of the partitions.
# Find them using fdisk -l.
Offsets=($(fdisk -l test.img | egrep -A 10 'Device[ ]+Boot[ ]+Start' | tail -n +2 | awk '{print $3}'))

for Offset in ${Offsets[@]} ; do
    (( Offset = 512 * Offset ))
    echo "INFO: Offset=$Offset"

    LoopDevice=$(losetup -f)
    echo "INFO: LoopDevice=$LoopDevice"

    set -x
    sudo losetup -o $Offset $LoopDevice $ImgFile
    { set +x ; } 2>/dev/null

    echo "INFO: File system information"
    set -x
    sudo mke2fs -n $LoopDevice
    { set +x ; } 2>/dev/null

    echo "INFO: Fix file system"
    set -x
    sudo fsck -f -p -D $LoopDevice
    st=$?
    { set +x ; } 2>/dev/null
    echo -n "INFO: Status=$st "
    case $st in
        0)
            echo "No errors"
            ;;
        1)
            echo "File system errors corrected"
            ;;
        2)
            echo "File system errors corrected, system should be rebooted"
            ;;
        4)
            echo "File system errors left uncorrected"
            ;;
        8)
            echo "Operational error"
            ;;
        16)
            echo "Usage or syntax error"
            ;;
        32)
            echo "Canceled by user request"
            ;;
        128)
            echo "Shared library error"
            ;;
        *)
            echo "Uknown error"
            ;;
    esac
    
    set -x
    sudo losetup -d $LoopDevice
    { set +x ; } 2>/dev/null
done

echo "INFO: Done"