The attached dumpafm.pe uses fontforge to write out afms from a given 
dfont (or other multi-font) file. So, for example:
  /usr/local/bin/fontforge -script dumpafm.pe /Library/Fonts/Optima.dfont
...creates five new AFMs (with kerning pairs) in the current directory.

 From there, you can do the above two steps. Since afm2pl also creates 
mapfiles, you can do some extra CLI magic to stitch those together 
automatically.

We can probably take the rest of this off-list if you need further CLI 
help.

cheers,
adam