The brief version of my question is pretty much what the title says:
How can I safely determine which of the files currently in my iPod would be deleted or modified if I synchronized it in iTunes?
(The term "modified" is admittedly a bit fuzzy. If more precision is needed, I'll define "modified" to mean that the old and new versions are not "equal", where files A and B are defined to be "equal" if
diff A B produces no output to the terminal.)
(Of course, simply synchronizing the iPod and then "looking for what's missing or changed" is not an acceptable answer. If you need more details, please read on.)
As I explained in another post, as part of a troubleshooting effort, I would like to enable synchronization for my iPod, in iTunes.
Unfortunately, I am almost certain that synchronizing this iPod with my current iTunes library would result in the modification or outright deletion of many files from my iPod.
The obvious solution of backing up the entire iPod, and restoring it later, is not an option, simply because at the moment I do not have a sufficiently convenient 150GB of disk space that I could use for this. (In fact, the problem that motivates this post arose as I was trying to make some room in my hard drive.)
But I may have enough room to back up the subset of those files now in my iPod that would be deleted or modified upon synchronization. Hence the question posed at the beginning of this post.