Reference: here

Upgreate Wheezy to Jessie

Make a script

sudo nano autosizer.sh

Insert the followin into the file:

#!/bin/bash
# Automatic Image file resizer
		# Written by SirLagz

strImgFile=$1
export PATH=$PATH:/sbin
if [[ ! $(whoami) =~ “root” ]]; then
	echo “”
	echo “**********************************”
	echo “*** This should be run as root ***”
	echo “**********************************”
	echo “”
	exit
fi
if [[ -z $1 ]]; then
	echo “Usage: ./autosizer.sh ”
	exit
fi

if [[ ! -e $1 || ! $(file $1) =~ “x86” ]]; then
	echo “Error : Not an image file, or file doesn’t exist”
	exit
fi

partinfo=`parted -ms $1 unit B p`
		existRootPart=`echo “$partinfo” | grep -o ‘B:ext4:\|B:ext3:’`
		numberOfMatchPart=`echo “$existRootPart” | wc -l`
if [[ $existRootPart == “” || $numberOfMatchPart -eq 0 || $numberOfMatchPart -gt 1 ]] ; then
	echo “Error : Your partition layout is not currently supported by this tool.”
	exit
fi

fileSystemType=`echo “$existRootPart” | cut -d: -f2`
partnumber=`echo “$partinfo” | grep $fileSystemType | awk -F: ‘ { print $1 } ‘`
partstart=`echo “$partinfo” | grep $fileSystemType | awk -F: ‘ { print substr($2,0,length($2)) } ‘`
loopback=`losetup -f –show -o $partstart $1`
e2fsck -f $loopback
minsize=`resize2fs -P $loopback | awk -F’: ‘ ‘ { print $2 } ‘`
minsize=`echo $minsize+1000 | bc`
resize2fs -p $loopback $minsize
sleep 1
losetup -d $loopback
partnewsize=`echo “$minsize * 4096” | bc`
newpartend=`echo “$partstart + $partnewsize” | bc`
parted $1 rm $partnumber
parted $1 unit B mkpart primary $partstart $newpartend
endresult=`parted -m $1 unit B print free | tail -1 | awk -F: ‘ { print substr($2,0,length($2)) } ‘`
truncate -s $endresult $1

Save and exit editor