Compare two directories with GSBA files.

compare-dirs-with-gsba-files.sh

#!/usr/bin/env sh
#
# A POSIX-compliant shell script that compares the contents of GSBA files,
# created by the GameSave Manager [1] Windows application. Such files are
# essentially ZIP files with a GSM_INFO.xml metadata descriptor.
#
# The script accepts two directories as the arguments; the first is treated as
# containing "old" files, and the second, the "new" files. Only games in the
# second directory are compared with their counterparts.
#
# [1] https://www.gamesave-manager.com/

OLD_FILES_DIR="$(readlink -f "$1")"
NEW_FILES_DIR="$(readlink -f "$2")"

if [ ! -d "$OLD_FILES_DIR" ] || [ ! -d "$NEW_FILES_DIR" ] ; then
  exit 1
fi

OLD_FILES="$(mktemp -d --suffix="-old")"
NEW_FILES="$(mktemp -d --suffix="-new")"

find "$NEW_FILES_DIR" -type f -iname "*.gsba" -printf "%p\n" \
  | sort -u \
  | while IFS= read -r NEW_FILE_PATH ; do
      GAME_NAME="$(basename "$NEW_FILE_PATH" \
        | awk -F"_" '{print $1}' \
        | sort -u)"
      OLD_FILE_PATH="$(find "$OLD_FILES_DIR" -type f -iname "$GAME_NAME*.gsba" \
        | sort -u \
        | head -1)"

      if [ -n "$OLD_FILE_PATH" ] ; then
        unzip -q "$OLD_FILE_PATH" -d "$OLD_FILES" -x GSM_INFO.xml
      else
        mkdir "$OLD_FILES"
      fi

      unzip -q "$NEW_FILE_PATH" -d "$NEW_FILES" -x GSM_INFO.xml

      DIFF="$(diff --brief --recursive --text "$OLD_FILES" "$NEW_FILES")"
      if [ -n "$DIFF" ] ; then
        echo "$GAME_NAME"
        echo "$DIFF"
        echo
      fi

      rm -rf "$OLD_FILES" "$NEW_FILES"
    done