[plug] ghostscript or similar tweak needed

[Gavin Chester]

I've scanned parts of an 'out of print' book for personal research
(within fair use conditions, and all that) and saved it as a multipage
pdf using xsane. Trouble is, to fit the book on the scanner bed in a
'sane' way, I had to rotate the book upside down for all the facing
pages. Does anyone know if I can use ghostscript or some other tool
combined with a little scripting to go thru' the document and rotate
every other page 180deg before saving it as a new pdf file?

Gavin