Can you delete list TAGs in an ARGFILE?

[mdcrovitz]

I'm observing that tag commands like "iptc:Keywords=" and "mwg:keywords=" have no effect if included in an ARGFILE, while the same command on the command line work fine. I get the same results with either TAG -- the command does nothing if in an ARGFILE, but works as expected on teh command line.

This is an extract from from my ARGFILE:

-mwg:Keywords=
-mwg:Keywords=#1: MWG Test KW #1
-mwg:Keywords+=#2: MWG Test KW #2
-mwg:Keywords+=#3: MWG Test KW #3

Keywords are not getting cleared, rather they growing in number each time I rerun the Argfile. ie, if I run the command line "exiftool mwg:keywords= test.jpg" the keywords are deleted as expected.


Any thoughts on how I can clear then rewrite a list of keywords?

[Phil Harvey]

The problem isn't the argfile.  The same thing will happen with those arguments on the command line.  The reason the keywords aren't getting deleted is because you are using +=, which indicates that you want to add new values to existing keywords.  This implies that you want to keep existing keywords, so exiftool doesn't delete them.

Instead, what you want is this:

-mwg:Keywords=#1: MWG Test KW #1
-mwg:Keywords=#2: MWG Test KW #2
-mwg:Keywords=#3: MWG Test KW #3


- Phil

[mdcrovitz]

Thanks for replying to my question. I still have one more question though.

Consider the 4 line ARG File I listed in my inital post. I'd have thought that Line 1 would have cleared all keywords, Line 2, would have added the first KW, Lines 3 and 4 added KWs for a total of 3 KW. Further, If I were to apply this ARG file to the same JPEG file twice in a row, and dump the KWs between the two ARG file applications, I'd expect to see 3 keyword listed each time. This is not what I see.

The first time I run the ARG file, I do see 3 keywords. However, when I run the ARG file on the same JPEG file a  second time, I see 6 keywords an exact doubling of KW (1, 2, 3, 1, 2, 3). It is  like Line 1 of the ARG file is getting ignored because another line in the ARG file used the accumulate operator (+=).

How would I strucutre my ARG file to manage an arbitrary JPEG file that will set only the KWs I provide in the ARG file and not append KWs to any prior existing KWs?

[Phil Harvey]

This is a common misunderstanding, which I attempt to explain in FAQ number 17.

The basic problem is:  It is easy to think that += and -= add and delete from the list of keywords they are writing, but they don't.  Instead they add and delete from the keywords that already exist in the file.

If you want to start fresh and ignore the keywords that already exist in the file, then don't use += or -= when you write new keywords.  Existing keywords will be overwritten.  It is as simple as that.  This is the way exiftool works for all tags.

- Phil