35 lines
904 B
Bash
Executable File
35 lines
904 B
Bash
Executable File
#!/bin/bash
|
|
# Copies raspi3.img into compr.img, resulting in many consecutive zero bytes
|
|
# which are nicely compressible.
|
|
|
|
set -e
|
|
|
|
qemu-img create -f raw compr.img 1000M
|
|
|
|
# copy partition table from raspi3.img
|
|
sfdisk --quiet --dump raspi3.img | sfdisk --quiet compr.img
|
|
|
|
readarray rmappings < <(sudo kpartx -asv raspi3.img)
|
|
readarray cmappings < <(sudo kpartx -asv compr.img)
|
|
|
|
# copy the vfat boot partition as-is
|
|
set -- ${rmappings[0]}
|
|
rboot="$3"
|
|
set -- ${cmappings[0]}
|
|
cboot="$3"
|
|
sudo dd if=/dev/mapper/${rboot?} of=/dev/mapper/${cboot?} bs=5M status=none
|
|
|
|
# copy the ext4 root partition in a space-saving way
|
|
set -- ${rmappings[1]}
|
|
rroot="$3"
|
|
set -- ${cmappings[1]}
|
|
croot="$3"
|
|
sudo e2fsck -y -f /dev/mapper/${rroot?}
|
|
sudo resize2fs /dev/mapper/${rroot?} 700M
|
|
sudo e2image -rap /dev/mapper/${rroot?} /dev/mapper/${croot?}
|
|
|
|
sudo kpartx -ds raspi3.img
|
|
sudo kpartx -ds compr.img
|
|
|
|
bzip2 -k -9 -f compr.img
|