backup raspberry pi image

pi-image-backup.md

on OSX:

1. backup whole disk

# check micro sd card disk

$ diskutil list

# copy whole disk, /dev/disk2 is the sd card devcie, the size is 16G

$ sudo dd if=/dev/disk2 bs=4m | pv -s 16G | sudo dd of=pi.img bs=4m

2. shrink the image

# download https://github.com/thhan/Docker-PiShrink, and copy pi.img to Docker-PiShrink

$ ./docker.sh 

# inside docker container

$ pishrink pi.img
$ gzip -9 pi.img