How to change internal page numbers in the meta data of a PDF?

Question

I have a pdf document I created through non-Acrobat means (printing to pdf, then merging a bunch of pdfs), but I'd like to manually change the page numbers (i.e. the first several pages are simply title pages, the page that is labeled "page 1" is really the 7th sheet of the pdf). What's the simplest (and ideally, free) way to do this?

To be clear, I am not trying to change the numbers on the pages themselves, but the page numbers in the "metadata" that the pdf stores (the pages themselves are already numbered correctly; I just want "go to page 1" to go to the page labeled 1, which could be sheet 7).

For what it's worth, I'm on Windows, though I have access to Macs as well.

Answer 1

For removing the old ones, probably the easiest cross-platform way is just to crop the old ones off. You could to this, for example, with BRISS.

Adding the new ones using free tools is more tricky. Personally I'd probably do it with pdflatex, as in this StackExchange answer, though that might be a rather involved solution unless you have other uses for pdflatex.

I think it can be done, however with jPdfTweak instead.

Answer 2

If I understand you correctly, here is how it should work:

gs \
  -o modified-pagelabels-50pages.pdf \
  -sDEVICE=pdfwrite \
  -c "[ /Page 1 /Label (i)     /PAGELABEL pdfmark" \
  -c "[ /Page 2 /Label (ii)    /PAGELABEL pdfmark" \
  -c "[ /Page 3 /Label (III)   /PAGELABEL pdfmark" \
  -c "[ /Page 4 /Label (four)  /PAGELABEL pdfmark" \
  -c "[ /Page 5 /Label (v)     /PAGELABEL pdfmark" \
  -c "[ /Page 6 /Label (|||||) /PAGELABEL pdfmark" \
  -f 50pages.pdf

However, I seem to remember, that this didn't reliably or fully work last time I tried this (about 2 years ago).

UPDATE: My memory wasn't failing me. I now tried again and filed a bug report for Ghostscript (bug 691889) concerning this. Follow the link to the bug report to see the details.