PDF Metadata Erasure
You cannot erase pdf metadata with exiftool
(it only appends your changes).
To delete pdf metadata, you'll need gs
.
Make a text file called 'pdfmark.txt'.
1[ /Title ()
2/Author ()
3/Subject ()
4/Creator ()
5/ModDate ()
6/Producer ()
7/Keywords ()
8/CreationDate ()
9/DOCINFO pdfmark
Then run:
1gs -o output.pdf -sDEVICE=pdfwrite "$FILE".pdf pdfmark.txt