[ns] animated gifs from ns

[Robin Poss <robin@ee.cornell.edu>]

hello, 
I would like to make an animated gif from a nam ouput.
I foud these instructions in the nam manual:
The following shell script (sh, not csh) converts these files into an animated gif: 

for i in *.xwd; do
        xwdtoppm <$i |
        ppmtogif -interlace -transparent'#e5e5e5' >`basename $i .xwd`.gif;
done
gifmerge -l0 -2 -229,229,229 *.gif >movie.gif

however , after having installed with difficulty pbmplus from
http://www.acme.com/software/pbmplus/, and gifmerge from
http://www.the-labs.com/GIFMerge/, it still doesn't work.

I would appreciate any ideas about other ways to make this
animated gif, as well as pointers towards more recent versions of
xwdtoppm, pbmplus and gifmerge.
thanks, 

-- 
Robin