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I'm backing up 2 drives to an external backup drive. The 2 source drives have a lot of duplicate files (name/size) between them (for work). One of the source drives is already backed up to the destination drive. I'd like to backup the second source drive to the same destination drive, different directories, but not include any files with the same name and size if they already exist somewhere on the destination drive. Is there a backup or copy program that can index the destination drive and then check the index for each source drive file, to prevent duplicate backed-up files scattered on the destination drive?



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for Windows, Linux, Mac ? – malakrsnaslava Jan 27 '13 at 1:40
Sorry, Windows - but I can run Cygwin in Windows. – Bruce Jan 27 '13 at 2:16

Most backup utils have a means of performing an incremental backup, essentially what you're describing when you mention copying files based on pre-indexing the destination. However, since you've already started the process by copying files manually, if your host system is Windows, you could try XXCOPY. It has literally dozens of command-line switches to determine what will/won't be copied.

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