I'm pretty sure I'm in over my head with this one.

Here's the situation:
My practice has been, after downloading and making changes to files, to use a certain GUI cataloging app to move them to appropriate categorized sub-folders inside one "umbrella" folder, then copy them to (what are in most cases) identically-named sub-folders in another one on the same HD.

Emulation of this process on the command-line would look like:
This was in anticipation of making a "twin" of the second, now bigger, "umbrella" folder on anexternal HD and continuing the practice. At some point I intended to get rid of the original 2nd "parent folder" and just keep the first one on the drive with my OS install, using the twin on the backup folder as I'd been doing when it was on that same drive.

I'm very close (a matter of 2 to 3 weeks, it looks like) to getting a backup/external drive in a reasonably-reliable external enclosure. With the backup, originally the "twin" of the bigger "umbrella" folder and its sub-directories, on that other drive, I also anticipate that I will likely go at least a few days between backing up any new files to it.

For the sake of argument, let's say I gave the external the name "tuxs_twin". Is there any way to monitor copying activity from /Pictures/ on the boot HD to /media/tuxs_twin/Pictures/ and log the dates and times, then have something running that checks the log every so many hours and puts up a reminder dialog saying /tuxs_twin/Pictures/ hasn't had any new files copied to it since date X at time Y?

I hope this was clear enough. If not, I'll try to break it down further when I know which details are confusing folks.

BZT

If it needs to be real-time then maybe something based on Inotify, an Auditd rule or FUSE LoggedFS? Else why not use 'rsync'?


Like updating the destination using 'rsync' with the "-n" switch?

I had thoughts along those lines, to tell the truth. A part of my brain said, "This is rsync stuff, but almost in reverse." Because if nothing's changed between the two parent folders, there's nothing to "report" to the user (me), and consequently nothing for rsync to do.

Auditd under/with LoggedFS looks very good for this. I see from the Sourceforge project page that tasks to be monitored are read from editable XML files -- very cool, imo.

Thanks for the suggestions.

BZT