EDIT: I missed the purpose of the task - if you just want to automate backup of changed files/entries, the answers below are enough and better than this one.
There's no tool for that.
You can however get a JSON export of your backup and your current library and then use a JSON comparer. You'll need MC Server enabled for this:
- backup in case this goes wrong
- export current lib using a browser, save it to
current.json http://
YourMCServer:52199/MCWS/v1/Files/Search?Action=json
- create a new empty Library, switch to it
- restore the backup you wish to compare into this empty library
- export it using the same URL, save to
backup.json- switch back to your original library
You can use an online JSON compare tool like this one:
https://jsoncompare.org/If the dumps are too large, you'll need to find another tool that can do it.
Edit: this will probably only work for smallish libraries due to the size of the export. For larger ones you should get the export with "wget
url_above -O export.json" and find some tool that can compare huge json files. Or write your own.