Upgrade to Debian Bookworm

to_bookworm.sh

find /var/lib/apt/lists/ -mindepth 1 -maxdepth 1 -type f -size +0 -print -delete

file=/etc/apt/sources.list
if [ -f "$file" ]; then
  owner=$(stat -c %U:%G "$file")
  perms=$(stat -c %a "$file")
  mv -v "$file" "$file.$(date +%y%m%d%H%M%S)"
fi
[ -z "$owner" ] || owner="root:root"
[ -z "$perms" ] || perms=644
cat <<EOF >"$file"
deb http://deb.debian.org/debian/ bookworm main
deb http://security.debian.org/debian-security bookworm-security main
deb http://deb.debian.org/debian/ bookworm-updates main
EOF
chown $owner "$file"
chmod $perms "$file"

apt-get update