Lyssaria mentions how to do this casually in this post.

However, it should be noted that there is no specific "command" to backup the files, and you should definitely not open them, as that does have a chance to corrupt the files, which will make them unplayable.

To backup your savegame files, simply follow the more precise directions available here. There are no extra programs needed, but we do recommend you be familiar with copying files before attempting these procedures.

I hope this helps!