Resizing postscript files.

Use pstops. For example the following command doubles-up the postscript file, removing blank space:

pstops -p a4 "2:0@.9L(24cm,-2cm)+1@.9L(24cm,12.85cm)" original.ps new.ps

This one uses psnup to put the slides printed by beamer four to a sheet.

psnup -pa4 -W363 -H273 -4 -d5 -m10 -b5 -c algobj.handout.ps > algobj.handout_nup.ps

Merge PDFs with ghostscript

This took me absolutely ages to find out about. I'd been trying all sorts of silly things, almost including trying to edit the PDFs directly!

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=merged.pdf \
source1.pdf source2.pdf source3.pdf etc.pdf