Command line to plot pdf

Well you could use git to achieve something similar. (Or even better)
see this forum post: (especially the link in the first post)

With that you have the added benefit that you have the old project files in the version control.
And with the graphical diff tool you can even see what changed between commits.

I’m not sure if the diff tool in the linked post is finished.
Here is an alternative if you are interested.

It could even be used to do what you want to achieve without git.