Anonymizing PDF files

Some PDF viewers allow you to add annotations which are embedded in the PDF file itself. This is a problem if one later wants to share the PDF with other people. Moreover, some publishers add text to downloaded PDF files that track who downloaded a particular file from their website. This is just a short list of pdftk invocations to strip unwanted information from a PDF.

Annotations

To strip annotations added by Okular:

pdftk PDF_FILE.pdf output - uncompress | sed '/^\/Annot *okular*/d/' | pdftk - output STRIPPED.pdf compress

Trackers

Something like the below should suffice to remove publisher-added tracking information:

pdftk PDF_FILE.pdf output - uncompress | sed "s|INTER-UNIVERSITY CENTRE FOR ASTRONOMY AND ASTROPHYSICS|Aaron|g" | sed "s|IUCAA|MIT|g" | sed "s|on ../../..|on 11/Jan/13|g" | pdftk - output JACK_SPARROW.pdf compress

Original source

https://stackoverflow.com/questions/49598797/remove-pdf-annotations-via-command-line#49614525