Alphabetize list-type tags

[wywh]

how you got the empty element without trying unless natcomp generated it

I believe natcomp generated it when I was trying to clear old Subject list with minimum effort with Subject=''.

After deleting natcomp block from the command it works as expected and Subject line is nuked:

Code Select Expand

exiftool -a -G1 -s -sep '//' -XMP:All image.jpg                                    
[XMP-dc]        Subject                         : a

exiftool -tagsFromFile @ -XMP-dc:Subject -XMP-dc:Subject='' -api NoDups=1 -execute '-Subject<${Subject;$_=join ";", sort{natcomp} split ";"}' -common_args -m -P -overwrite_original -sep ';' image.jpg
    1 image files updated
    1 image files updated

exiftool -a -G1 -s -sep '//' -XMP:All image.jpg
[XMP-dc]        Subject                         :

exiftool -tagsFromFile @ -XMP-dc:Subject -XMP-dc:Subject='' -api NoDups=1 -m -P -overwrite_original -sep ';' image.jpg
    1 image files updated

exiftool -a -G1 -s -sep '//' -XMP:All image.jpg
[null]
-Matti

[StarGeek]

-XMP-dc:Subject=''

on the command line is equivalent to:

-XMP-dc:Subject=

because the quotes are stripped by the command shell.

I don't know what I did but I did a quick test before and ended up with a 0 length tag.  Of course, now I can't reproduce it, so I did something wrong.

But I don't know how you got the empty element without trying unless natcomp generated it.

I hope not.  I tested a file using wywh's command and it didn't happen for me.  Back to testing it is.

[StarGeek]

Ah, there it is.  You have the -m (-ignoreMinorErrors) option option in the command.  You are clearing Subject before the -TagsFromFile, but then copying the empty Subject back into itself. From the docs

Note that this causes missing values in -tagsFromFile, -p and -if strings to be set to an empty string rather than an undefined value.

Example:

Code Select Expand

C:\>exiftool -G1 -a -s -subject y:\!temp\Test4.jpg

C:\>exiftool -G1 -a -s -m "-Subject<$Subject" y:\!temp\Test4.jpg
    1 image files updated

C:\>exiftool -G1 -a -s -subject y:\!temp\Test4.jpg
[XMP-dc]        Subject                         :

[Phil Harvey]

Yes.  That will do it.

- Phil

[wywh]

Ah, there it is.  You have the -m (-ignoreMinorErrors) option option in the command

Thanks again. I have used -m because AFAIR in some distant past some command failed without it, and also as a means to prevent benign warnings from littering the output. So I deleted it form the command below. To clear old Keywords, use just Subject='', and then start to fill the Keyword list again. No more empty Subject string left behind.

Code Select Expand

exiftool -XMP-dc:Title='Title' -XMP-photoshop:CaptionWriter='Author' -XMP-dc:Description='Description' -XMP-xmp:Rating=3 -tagsFromFile @ -XMP-dc:Subject -XMP-dc:Subject='Keyword 1;Keyword 2' -api NoDups=1 -execute '-Subject<${Subject;$_=join ";", sort{natcomp} split ";"}' -common_args -P -overwrite_original_in_place -sep ';' image.jpg
- Matti

[wywh]

It seems it is best to avoid commas inside image IPTC:Keywords and XMP-dc:Subject (and also in movie Keys:Keywords) because macOS 14.2.1 Sonoma Photos.app forces comma as a Keyword separator anyway. If there is a comma inside a IPTC/XMP Keyword, then Photos.app splits the Keyword and the pieces are grayed out in its info dialog.

On the other hand, Photos.app accepts semicolon inside those image and movie Keywords.

I heard that Adobe XMP SDK treats semicolon and comma by default the same in Keywords.

- Matti