Do not perform any file operation if Tag-Value exists

[horst]

Hi,

this is my first question in this Forum as I couldn't find any answer to my following question on the FAQ, Google, etc.

I like to use Sidecards as *.json and update all JPG's within a folder with the Tags specified in this sidecard. Therefor I exported the Information from an example File with the -json parameter and modified it for my needs. I can now update all files within the current folder by just running

Code Select Expand

exiftool -r -progress -overwrite_original -json=./sidecard_new.json ./
This is working fine for me, but:

I like to automate the changes. So if I do change the Sidecard file, I want to re-run the operation.

Of course I could just regulary run the command to ensure the files are up to date. But all(!) files are written every time again, even if the Tag already exists and the value is the same.

Is there any way to tell ExifTool to just perform file operations if there are really changes to do?

Otherwise I would have to do some workaround ...

Thanks in advance!
Horst

[Phil Harvey]

Hi Horst,

The easiest thing to do is to maintain a list of files where you changed the metadata, then use this list in the command instead of updating the entire directory, like this:

exiftool -progress -overwrite_original -json=./sidecard_new.json -@ changed_files.txt

- Phil