Steve Izma wrote:
> I also find it much safer to keep a copy of the output of a complex
> project (like a book) as well as the source code; macro package
> interaction with groff can change in subtle ways over the years and
> you can't count on reproducing a book in precisely the same way by
> re-running it ten years later (or 15 or so years, as I've tried once
> or twice).
I've been bitten by this too, hence
groff's -mm macros have Moved the Footer in version 1.18.
https://launchpad.net/ubuntu/+source/groff/+bug/42764
I keep the output PostScript around now and have a crude ~/bin/psdiff
which, for two black and white PostScript files, produces a PPM per
page. If the same pixel is set on both versions of the page it comes
out black, else it's either red or blue depending on which version it's
set in. ppmhist(1) is an easy way to see if there's any red or blue
pixels in a "page".
So if you do have nicely formatted and checked output, it's worth
keeping it because groff a few years from now may not produce it the
same way, and spotting this may be non-trivial.
Cheers,
Ralph.
