It would be great to have a local partial mirror of Debian repository in a site with multiple system running Debian. If this is not the case, a quick way to distribute newly downloaded deb packages to other system. Of course, just copying the whole /var/cache/apt/archives works. rsync can be used to save time, network bandwidth, and perhaps temporary storage space.

To copy just new debs package from apt archive to another system, use this command (as normal user):

rsync -vv --progress --stats -r --size-only --exclude=partial/ --exclude=lock --compare-dest=/var/cache/apt/archives --ignore-existing /var/cache/apt/archives/ eve@punyaepapisissy.qnv:/tmp/arc/

Then use this command as root on the destination system (as root):

rsync -vv --progress --stats -r --size-only --ignore-existing /tmp/arc/ /var/cache/apt/archives/
rm -rf /tmp/arc