Technique for finding invalid bookmarks in a PDF file

I have been encountering invalid bookmarks on a regular basis within PDF files lately. I went looking for a technique that would allow me to quickly determine if there were any broken bookmarks in a PDF file.

The solution I came up with involves using pdftk [https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/] and your favorite MAC or Linux command line:

pdftk mypdf.pdf dump_data | grep -B 2 "PageNumber: 0"

Results:

BookmarkTitle: 10.2 Oxygen equipment
BookmarkLevel: 3
BookmarkPageNumber: 0
--
BookmarkTitle: 10.2.1 Chemical oxygen system:
BookmarkLevel: 4
BookmarkPageNumber: 0