[pdftex] Comparing Two PDF files

[Ben Crowell]

I'm interested in this myself, because I sometimes generate PDF
on my desktop machine, and sometimes on my server. I'd like some
assurance that the PDF I'm generating on the server, and serving
up to the public, isn't messed up. Also, you have to run tex
multiple times so that it converges on the right result, and it
would be nice to know that both had converged to the same final
result! I've tried using ``cksum'' to do this, and the results
are kind of interesting. I think I'm running identical versions
of pdflatex on both machines, but I get slightly different results.
The sizes are different by a few bytes, and the checksums are of
course different. Maybe pdftex embeds the current date somewhere
in the pdf file it generates?