apk-backup

#!/usr/bin/env bash

# Usage: apk-backup
#
# This makes a backup of all the installed APKs on your Android phone,
# because Google implemented an ass-backwards, self-serving, defective
# architecture where it is borderline impossible to find the previous
# version of an app you installed after the upgrade turns out to be
# nonfunctional. Run this script before every system upgrade and it
# will make a nice timestamped JSON report with the versions of all
# your apps, as well as extracting the actual APKs (deduplicated so
# that you can run this multiple times and not get multiple copies of
# the same version of the same app).

set -euo pipefail

log() {
    echo "[apk-backup] $(date +%H:%M:%S)" "$@"
}

ts="$(date +%Y-%m-%d-%H-%M-%S)"

log "Using timestamp ${ts}"

mkdir -p ~/.cache/apk-backup
cd ~/.cache/apk-backup

mkdir -p applists

log "Getting list of installed packages..."

allpkgs="$(

adb shell pm list packages -3 -i --show-versioncode

)"

pkgs="$(sed -E <<< "${allpkgs}" 's/^package:([^ ]+) +versionCode:([^ ]+) +installer=([^ ]+)$/pkg \1 \2 \3/')"

if grep -v '^pkg' >&2 <<< "${pkgs}"; then
    echo >&2 "fatal: bad line format from pm list packages"
    exit 1
fi

jq <<< "${pkgs}" -Rs 'split("\n") | map(split(" ") | select(length == 4) | {name: .[1], version: .[2], installer: .[3]}) | unique | sort_by(.name)' > "applists/${ts}.json"

log "Getting list of installed packages... found $(jq length < "applists/${ts}.json")"

mkdir -p apks
find apks -name "*.tmp" | xargs rm -rf
jq < "applists/${ts}.json" '.[] | "\(.name) \(.version)"' -r | while read -r pkg ver; do
    if [[ -d "apks/${pkg}/${ver}" ]]; then
        continue
    fi
    log "Copying new APK(s) for ${pkg} version ${ver}..."
    mkdir -p "apks/${pkg}/${ver}.tmp"
    apks="$(adb shell pm path "${pkg}" </dev/null | sed 's/^package://')"
    while read -r apk; do
        filename="$(basename "${apk}")"
        adb pull "${apk}" "apks/${pkg}/${ver}.tmp/${filename}"
    done <<< "${apks}"
    mv "apks/${pkg}/${ver}.tmp" "apks/${pkg}/${ver}"
    log "Copying new APK(s) for ${pkg} version ${ver}... got $(wc -l <<< "${apks}")"
done

ln -sf "applists/${ts}.json" applist.json

log "Finished!"