backup raspbian( stretch 2018.04.18 ) to a small img

raspbian-1804-backup.sh

#!/bin/sh
sudo apt-get install -y dosfstools parted kpartx rsync
df=`df -P | grep /dev/root | awk '{print $3}'`
dr=`df -P | grep /dev/mmcblk0p1 | awk '{print $2}'`
df=`echo $df $dr |awk '{print int(($1+$2)*1.2)}'`
sudo dd if=/dev/zero of=raspberrypi.img bs=1K count=$df
sudo parted raspberrypi.img --script -- mklabel msdos
start=`sudo fdisk -l /dev/mmcblk0| awk 'NR==10 {print $2}'`
start=`echo $start's'`
end=`sudo fdisk -l /dev/mmcblk0| awk 'NR==10 {print $3}'`
#end2=$[end+1]
end2=`sudo fdisk -l /dev/mmcblk0| awk 'NR==10 {print $2}'`
end=`echo $end's'`
end2=`echo $end2's'`

sudo parted raspberrypi.img --script -- mkpart primary fat32 $start $end
sudo parted raspberrypi.img --script -- mkpart primary ext4 $end2 -1

loopdevice=`sudo losetup -f --show raspberrypi.img`
device=`sudo kpartx -va $loopdevice | sed -E 's/.*(loop[0-9])p.*/\1/g' | head -1`
device="/dev/mapper/${device}"
partBoot="${device}p1"
partRoot="${device}p2"
sudo mkfs.vfat $partBoot
sudo mkfs.ext4 $partRoot
sudo mount -t vfat $partBoot /media
sudo cp -rfp /boot/* /media/
sudo umount /media
sudo mount -t ext4 $partRoot /media/
cd /media
sudo rsync -aP --exclude="raspberrypi.img" --exclude=/media/* --exclude=/sys/* --exclude=/proc/*  --exclude=/tmp/* / ./
cd
sudo umount /media
sudo kpartx -d $loopdevice
sudo losetup -d $loopdevice