shell.sh

#!/bin/bash

image_url=$(realpath $1)
image_name=$(basename $image_url .img)
mkdir shell_workdir || true
packer build -var 'image_url='"$image_url"'' -var 'image_name='"$image_name"'' shell.pkr.hcl &

# shellcheck disable=SC2010
if startCount=$(ls -l /tmp/armimg-* | grep -c ^d); then
	echo "ok"
else
	startCount=0
fi
# shellcheck disable=SC2010
until [ "$( (ls -l /tmp/armimg-* || true) | grep -c ^d)" -gt "$startCount" ]; do
	sleep 5
done
tset                                      # packer messes up the shell, so reset the shell settings, no clear
ARMDIR=$(ls -td /tmp/armimg-*/ | head -1) # get latest
echo "run sudo chroot $ARMDIR in another shell to also log into the image. Stop by running rm /stopshell"

sudo chroot "$ARMDIR" && (rm "$ARMDIR"/stopshell || true)
wait

# shrink image, dont add autoexpand, otherwise image will not boot and just keeps restarting
sudo ./pishrink.sh -s -Z -a -v "./shell_workdir/$image_name.img" "./shell_workdir/$image_name-shrunk_$(date +"%Y-%m-%d_%H_%M_%S").img"