What's the best way of comparing two directory structures and deleting extraneous files and directories in the target location?
I have a small web photo gallery app that I'm developing. Users add & remove images using FTP. The web gallery software I've written creates new thumbnails on the fly, but it doesn't deal with deletions. What I would like to do, is schedule a command/bash script to take care of this at predefined intervals.
Original images are stored in
/home/gallery/images/ and are organised in albums, using subdirectories. The thumbnails are cached in
/home/gallery/thumbs/, using the same directory structure and filenames as the images directory.
I've tried using the following to achieve this:
rsync -r --delete --ignore-existing /home/gallery/images /home/gallery/thumbs
which would work fine if all the thumbnails have already been cached, but there is no guarantee that this would be the case, when this happens, the thumb directory has original full size images copied to it.
How can I best achieve what I'm trying to do?