Need to do a diff of two large folders (1.56 GB each)

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Level 1

46 points

Need to do a diff of two large folders (1.56 GB each)

I have two folders which are huge with thousands of files, one is complete the other an incomplete copy of the first, except that the second contains newer files.

I need to do a diff of the two folders and / or merge them without errors (getting the most up to date versions of each file: they are pdfs).

What would be the most foolproof method of accomplishing this? I rely on these for my work and need the best composite version of these two large folders.

Thanks.

MacBook Pro 14″, macOS 12.0

Posted on Nov 15, 2021 9:45 PM

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Answer 1

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MartinR

Level 6

18,947 points

Nov 19, 2021 4:44 PM in response to jinet

I wouldn't directly compare Visual Differ and Carbon Copy Cloner. While they can both copy files from a source to a destination they work very differently. You have more direct control over the sync/merge process with Visual Differ. In your scenario I think Visual Differ is the better approach.

With CCC you have to designate a Source and a Destination (disk or folder). CCC then compares files based on size & modification date and assumes that files on your Source are the correct versions. If the size or modification date of a file is different in any respect on the Source vs. Destination, CCC will copy the file that's on the Source to the Destination. This may lead to undesirable results.

Visual Differ requires user involvement but I find that desirable in most cases where I want to sync two folders or disks.

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Answer 2

MartinR

Level 6

18,947 points

Nov 16, 2021 6:07 PM in response to jinet

VisualDiffer from the Mac App Store. Fantastic utility. I use it all the time to compare and merge folders and drives.

It can compare file names, content, sizes, timestamps and various combinations of the same.

One of the nice features is that you can have it show only 'orphans' in each folder (files that exist in one folder but not the other), which makes it really easy to merge files missing from one or the other of the folders being compared.

It can also show you files that are present in both folders but different in some respect (for example, having different date/time stamps, often an indicator of an updated version of one of the files).

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Answer 3

jinet Author

Level 1

46 points

Nov 16, 2021 7:16 PM in response to MartinR

Thanks for the tip. I will investigate the app. How do you think it compares with CCC? I use CCC for backups some of the time, and it just occurs to me that it could do a diff too (not sure about CCC's merge capabilities; I think it has them if it copies only the latest versions, if those are what you want to have copied).

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