I want to copy new files from my NAS to my external hard drive. I did copy the new files manually up to this point. Now I want to use a script to automate this for me. However everything I tried so far with rsync seems to copy all files and not only the new files. I tried with the following command:

rsync -ar \
      --ignore-existing \
      --size-only \
      --progress --info=progress2 \
      --dry-run \
      "/Volumes/NAS" "/Volumes/G-DRIVE mobile SSD R-Series"

I also tried without size-only, with checksum etc. Can somebody explain the behaviour to me or what I need to do in order to complete my task? When printing stats it always shows that it would transfer all the files. Also with the -i parameter I get the following information for every file: >f++++++++++

  • Ok I quickly checked the metadata and found that the creation date is different f.e "kMDItemContentCreationDate = 2012-01-28 05:59:13 +0000" vs. "kMDItemFSCreationDate = 1970-01-01 00:00:00 +0000". However the size (kMDItemFSSize = 1170942) seems to be the same and I thought with the size-only option this should work.
    – dehlen
    Commented May 18, 2023 at 15:10
  • This worked fine for me.
    – Cyrus
    Commented May 18, 2023 at 22:28
  • 1
    Thanks I found the solution in the accepted answer from your link. I was missing a trailing slash in the source folder which was causing the problem :)
    – dehlen
    Commented May 19, 2023 at 6:35

1 Answer 1


The correct command should probably be this:

rsync --archive --progress --info=progress2 \
    '/Volumes/NAS/' '/Volumes/G-DRIVE mobile SSD R-Series'

The -a (--archive) flag implies -t (--times) and -r (--recursive) so you don't need to specify those explicitly. Using --size-only is a poor choice when you have size and timestamp available from using -a (--archive), but if you're copying to a limited filesystem such as FAT you may need a time window such as --modify-window=2 to overcome the two second time granularity. You shouldn't use --ignore-existing unless you want to ignore changes to the source files once you've got a copy of any sort on the destination.

Definitely use --dry-run (-n) while testing, but remember to remove it when you're ready for the rsync action to be applied.

Finally, the source directory should usually have a trailing slash. The documentation describes it like this,

A trailing slash on the source changes this behavior to avoid creating an additional directory level at the destination. You can think of a trailing / on a source as meaning "copy the contents of this directory" as opposed to "copy the directory by name".

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