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The headline says it all I hope but just in case I'll ellaborate.

File A is a word file with 50 pages, it's size is 47 kb. File A is copied from source folder to destination folder.

File A is then changed. A couple of sentences here and there, maybe a page is added. It's size is now 50kb.

If robocopy at this point would be run with the /mir switch, would it delete the destination file and do a full copy, copying 50kb, or would it only update/add the 3kb into the existing file?

If it only adds the 3kb, like I want it do - great! Would this also work on video files (avi, mkv etc) that are being downloaded through torrent?

I believe basically what I'm asking is is if robocopy does binary diff/compares binary on single files and then adds changes.

share|improve this question
Why not just try it? But I'm pretty sure the answer is no, since it's scope is the folder, not the files. – Ƭᴇcʜιᴇ007 Apr 13 '13 at 19:36
Yea, I tried it. It justs overwrites. – evilperro Apr 13 '13 at 20:12

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