Script for updating Alpine diskless installs to the latest version: without canning it!

alpineUpgradeDiskless.sh

#!/bin/bash

echo "Getting last image..."
LastImage="$(curl -s https://dl-cdn.alpinelinux.org/alpine/latest-stable/releases/x86_64/ | sed -n 's/.*"\(alpine-extended-[[:digit:]\.]*-x86_64.iso\)".*/\1/p' | sort -r | head -n 1)"

LastVer="$(echo $LastImage | sed -n 's/alpine-extended-\([[:digit:]\.]*\)-x86_64.iso/\1/p')"
LastMVer="$(echo $LastVer | sed -n 's/\([[:digit:]]*\.[[:digit:]]*\).*/\1/p')"

CurrentVer="$(cat /media/usb/.alpine-release | sed -n 's/alpine-extended-\([[:digit:]\.]*\).*/\1/p')"
CurrentMVer="$(echo $CurrentVer | sed -n 's/\([[:digit:]]*\.[[:digit:]]*\).*/\1/p')"

echo "Current boot media is $CurrentVer, latest is $LastVer"

if [ "$CurrentVer" == "$LastVer" ]; then echo "Already up to date."; return; fi

while true; do
    read -p "Do you want to upgrade Alpine? [N] " yn
    case $yn in
        [Yy]* ) break;;
        [Nn]* ) exit;;
        * ) echo "Please answer yes or no.";;
    esac
done


echo "Upgrading all packages for current version before backup"

sudo apk -U upgrade
sudo apk cache -v sync

sudo lbu st

while true; do
    read -p "Do you want to commit first (You do)? [N] " yn
    case $yn in
        [Yy]* ) sudo lbu ci; break;;
        [Nn]* ) break;;
        * ) echo "Please answer yes or no.";;
    esac
done

sudo lbu ci

BackupFile="/tmp/$HOSTNAME-backup-$(date +'%Y%m%d-%H%M%S').tar.gzip"
sudo tar -caf $BackupFile /media/usb/cache /media/usb/$HOSTNAME*

echo "Make sure you download $BackupFile JUST IN CASE. Note that it's $CurrentVer as well."

while true; do
    read -p "Type READY to process. " rdy
    case $rdy in
        READY ) break;;
        * ) echo "Please type READY or break out.";;
    esac
done

if [ "$CurrentMVer" != "$LastMVer" ]; then echo "Repositories need an update first..."; sudo sed -i "s/$CurrentMVer/$LastMVer/g" /etc/apk/repositories; sudo apk -U upgrade; sudo apk cache -v sync; sudo lbu ci; fi

sudo setup-bootable -u "https://dl-cdn.alpinelinux.org/alpine/latest-stable/releases/x86_64/$LastImage"

echo "All set: Reboot."