Thursday, March 14, 2013

Linux Shell Script To Backup and Restore MBR Master Boot Record



Linux Shell Script To Backup and Restore MBR Master Boot Record


 

mbrback shell script creates a backup of your hard drive’s MBR and its partition table. You can then use mbrback to restore the MBR boot code, full MBR, or partition table from the backup files.

 


#!/bin/bash

# Script Name: mbrback    http://igurublog.wordpress.com/downloads/script-mbrback/

# Requires: util-linux

# License: GNU GENERAL PUBLIC LICENSE Version 3 http://www.gnu.org/licenses/gpl-3.0.txt


# do not change these variables!

argsneeded=1

restoretype=""

back=""

devname=""


help ()

{

echo 'mbrback version 1.0.0'

echo 'Creates MBR and partition table backups of DEVICE named:'

echo '    HOST-DEVICE-MBR-back'

echo '    HOST-DEVICE-partition-back.sf'

echo 'Restores MBR and partition table from specified backup file'

echo 'Usage: sudo mbrback DEVICE [BACKUPFOLDER]'

echo '       (creates backup files of DEVICE)'

echo 'Usage: sudo mbrback --restoreboot DEVICE [BACKUPFILE]'

echo '       (restores MBR boot code only)'

echo 'Usage: sudo mbrback --restorefullmbr DEVICE [BACKUPFILE]'

echo '       (restores entire MBR)'

echo 'Usage: sudo mbrback --restorepart DEVICE [BACKUPFILE.sf]'

echo '       (restores partition table)'

echo 'Example: sudo mbrback sda'

echo '         (creates MBR and partition table backups of'

echo '          /dev/sda in current folder)'

echo 'Example: sudo mbrback /dev/sda'

echo '         (creates MBR and partition table backups of'

echo '          /dev/sda in current folder)'

echo 'Example: sudo mbrback sda /mybackups'

echo '         (creates MBR and partition table backups of'

echo '          /dev/sda in /mybackups)'

echo 'Example: sudo mbrback --restoreboot sda /mybackups/sys-sda-MBR-back'

echo '         (restores MBR boot code of /dev/sda using'

echo '          /mybackups/sys-sda-MBR-back)'

echo 'Example: sudo mbrback --restorepart sda /mybackups/sys-sda-partition-back.sf'

echo '         (restores partition table of /dev/sda using sfdisk file '

echo '          /mybackups/sys-sda-partition-back.sf)'

echo

echo "When restoring, mbrback will always tell you what it's going to do"

echo "and allow you to abort before it writes to disk."

echo

echo "Instructions and updates:"

echo "http://igurublog.wordpress.com/downloads/script-mbrback/"

echo

}


index=0

while [ "$1" != "" ];

do

if [ "${1:0:1}" = "-" ]; then

case "$1" in

--help | -help )

help

exit

;;

--restoreboot )

if [ "$restoretype" = "" ]; then

restoretype="boot"

else

echo 'mbrback: can only use one restore option'

exit 1

fi

;;

--restorefullmbr )

if [ "$restoretype" = "" ]; then

restoretype="fullmbr"

else

echo 'mbrback: can only use one restore option'

exit 1

fi

;;

--restorepart )

if [ "$restoretype" = "" ]; then

restoretype="part"

else

echo 'mbrback: can only use one restore option'

echo

help

exit 1

fi

;;

* )

echo "mbrback: Unknown option $1"

echo

help

exit 1

;;

esac

else

let "index+=1"

case $index in

1 )

devname=`basename "$1"`

if [ ! -b "/dev/$devname" ]; then

echo "mbrback: /dev/$devname is not a valid device"

exit 1

fi

;;

2 )

back="$1"

;;

* )

echo "mbrback: Too many arguments"

exit 1

;;

esac

fi

shift

done

if (( index < $argsneeded )) || [ "$devname" = "" ]; then

echo "mbrback: missing arguments"

echo

help

exit 1

fi


if [ `whoami` != "root" ]; then

echo 'mbrback: must be run with sudo'

exit 1

fi


sysname=$HOSTNAME


if [ "$restoretype" = "" ]; then

# create MBR and table backups

if [ "$back" = "" ]; then

back=`pwd`

else

if [ ! -d "$back" ]; then

echo "mbrback: $back is not a valid backup folder"

exit 1

fi

fi

dd if=/dev/$devname of="$back/$sysname-$devname-MBR-back" bs=512 count=1

sfdisk -d /dev/$devname > "$back/$sysname-$devname-partition-back.sf"

else

# restore

if [ "$back" = "" ]; then

echo "mbrback: you must specify a backup file"

exit 1

elif [ ! -f "$back" ]; then

echo "mbrback: file not found - $back"

exit 1

fi

if [ "$restoretype" = "boot" ] || [ "$restoretype" = "fullmbr" ]; then

sfhead=`head --bytes=21 "$back"`

if [ "$sfhead" = "# partition table of " ]; then

echo "mbrback: $back is not an MBR backup file"

exit 1

fi

if [ "$(stat -c%s "$back")" != "512" ]; then

echo "mbrback: $back is wrong size for an MBR backup file"

exit 1

fi

fi

if [ "$restoretype" = "part" ]; then

sfhead=`head --bytes=21 "$back"`

if [ "$sfhead" != "# partition table of " ]; then

echo "mbrback: $back not a valid sfdisk backup file"

exit 1

fi

echo

echo "You are about to overwrite your /dev/$devname partition table with"

echo "the contents of $back"

echo

echo "WARNING!!! Unless the partition table has been damaged or you"

echo "           have accidentally deleted a partition, you should abort."

echo

echo "WARNING!!! Restoring the partition table from an out-of-date backup"

echo "           may render ALL the data on your drive unreadable."

echo

echo "WARNING!!! Do not proceed if /dev/$devname is mounted."

echo

elif [ "$restoretype" = "boot" ]; then

echo

echo "You are about to overwrite your /dev/$devname MBR boot code with"

echo "the contents of $back"

echo

echo "WARNING: Restoring your MBR boot code from an out-of-date MBR backup"

echo "         file may render your computer unbootable."

elif [ "$restoretype" = "fullmbr" ]; then

echo

echo "You are about to overwrite your ENTIRE /dev/$devname MBR with"

echo "the contents of $back"

echo

echo "WARNING!!! The full MBR contains both boot code and the drive's"

echo "           partition table.  Unless the partition table has been"

echo "           damaged or you have accidentally deleted a partition"

echo "           you should abort and restore boot code only with"

echo "           --restoreboot instead."

echo

echo "WARNING!!! Restoring your full MBR from an out-of-date MBR backup may"

echo "           render your computer unbootable and ALL the data on your"

echo "           drive unreadable."

echo

echo "WARNING!!! Do not proceed if /dev/$devname is mounted."

fi

echo

echo "Do you want to proceed? (you must type yes to proceed)"

read s1

if [ "$s1" != "yes" ]; then

echo "mbrback: no changes made - aborted at user request"

exit 2

fi

if [ "$restoretype" = "part" ]; then

sfdisk /dev/$devname < "$back"

elif [ "$restoretype" = "boot" ]; then

dd if="$back" of=/dev/$devname bs=448 count=1

elif [ "$restoretype" = "fullmbr" ]; then

dd if="$back" of=/dev/$devname bs=512 count=1

fi

echo "/dev/$devname was updated"

fi


exit 0


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