rpi3-resizerootfs

#!/bin/sh

roottmp=$(lsblk -l -o NAME,MOUNTPOINT | grep '/$')
rootpart=/dev/${roottmp%% */}
rootdev=${rootpart%2}
rootdev=${rootdev%p}

flock $rootdev sfdisk -f $rootdev -N 2 <<EOF
,+
EOF

sleep 5

udevadm settle

sleep 5

flock $rootdev partprobe $rootdev

mount -o remount,rw $rootpart

resize2fs $rootpart

exit 0