Small script to port xcas program changes made throughout hp prime backups to a git repo

import_hp_prime_backups_to_git_repo.sh

#!/usr/bin/env bash

decode_hp_xcas_program () {
    python3.8 -c '
import sys
enc = "utf-16le"
delims = ("#cas".encode(enc), "#end".encode(enc))
print(((lambda conts: conts[conts.find(delims[0])+len(delims[0]):conts.rfind(delims[1])])(
    open(sys.argv[1], mode="rb").read())).decode(enc))' \
        "$1"
}

extract_and_decode_backup () {
    local backup_file="$1"
    local extracted
    extracted="$(mktemp -d)" || return $?
    trap 'rm -rf "$extracted"' RETURN
    unzip -d "$extracted" -- "$backup_file" || return $?
    for program in "$extracted"/*.hpprgm; do
        echo "Decoding ${program@Q}"
        decode_hp_xcas_program "$program" > "${program%.*}.xcas" || return $?
        cp "${program%.*}.xcas" . || return $?
    done
}

# In my case these all happen to be ordered by date from old to new
# that way changes get commited in the right order
for bkp_file in ../*.zip; do
    rm -- * &&
    backup_date="$(stat -c '%y' -- "$backup_file")" &&
    extract_and_decode_backup "$bkp_file" &&
    git add . &&
    git commit -m "Add history from backup" --date "$backup_date"
done