Merging postscripts

This is essential and really difficult to find answers to, but this guy gave it:
http://ludo.qix.it/archive/2005/08/merge-postscript-files.html

The keywords I would have liked to see:
"merge postscripts into multi-page document"
or "combine postscript multiple page"

e.g.
gs -sDEVICE=pswrite -sOutputFile=output.ps -dNOPAUSE -dBATCH file1.ps file2.ps file3.ps

or

gs -sDEVICE=pswrite -sOutputFile=05358spectra.ps -dNOPAUSE -dEPSFitPage -dBATCH `ls 05358_*.eps`

(the added option is to make sure the .eps isn't cropped)