Create XMP sidecar files for unsupported file types?

[alex_work]

Hi everybody,

for my research data I am taking pictures of small crystals. With exiftool I am tagging these .jpg files so that I can search for specific crystals. Now I want to use the same tagging for the other files, e.g. text-files that describe these crystals or measured data files in binary formats.
Unfortunately I did not manage to tell exiftool that I want to tag for example "crystal1.txt" with a sidecar XMP file which contains metadata like author, date, keywords.
From the documentation it seems that exiftool (http://www.exiftool.org/metafiles.html) should be capable of tagging all kinds of file formats with a sidecar file but I cannot get it to work.
Is there any possibility to do this in exiftool or is there a better way to produce XMP sidecar files for binary and text files?

Thanks for any help!
Alexander

[Phil Harvey]

I don't know of any better way to do this.

You can generate a sidecar XMP by creating XMP from scratch with the same name as the .txt file:

exiftool FILE.xmp "-author=me"

Where FILE is the same name as some .txt file.

But as you said, exiftool can not be used to automatically generate sidecar files from .txt files because it isn't a supported format.

- Phil