(I had to correct this a couple of times, kindly look at the final version, please.)
Thanks!
Enscript (installed using HomeBrew) is a possibility, if "enscript.cfg" is modified so that the line
DefaultOutputMethod: printer
is changed to
DefaultOutputMethod: stdout
In that case, a pipe such as
enscript --filter="transcode-video --help" | pstopdf -l -o ~/desktop/onefile.pdf
is successful.
However, substituting
enscript --filter=$CMD | pstopdf -l -o $MANPDF
for
man -t $CMD | pstopdf -l -o $MANPDF
in the macro didn't work, apparently because "transcode-video --help" when entered into the dialog, is interpreted as two separate commands.
So that's one issue to be solved (my proficiency is mainly limited to AppleScript), and the second is to fork between the two command versions based on a conditional (should be easy to trap an error when either executable doesn't receive correct input).
I still used to get better results with "open -f -a /Applications/Preview.app" (before prepending the app path with "/System" was required).
"| open -f -a /Applications/Safari.app" is still beneficial to some extent, however.