"The fact that the easiest way to copy a program is from one neighbor to another, the fact that a program has both source code and object code which are distinct, and the fact that a program is used rather than read and enjoyed, combine to create a situation in which a person who enforces a copyright is harming society as a whole both materially and spiritually." Richard Stallman
/usr/local/Acrobat4/bin/acroread -toPostScript -pairs $1 /tmp/$1.ps
/usr/local/Acrobat4/bin/acroread -toPostScript -pairs $2 /tmp/$2.ps
a2ps --columns=1 -o /tmp/$1.both.ps /tmp/$1.ps /tmp/$2.ps
ps2pdf /tmp/$1.both.ps $3
rm -f /tmp/$1.ps
rm -f /tmp/$2.ps
rm -f /tmp/$1.both.ps
        gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=file.pdf -c save pop -f $1.pdf $2.pdf $3.pdf ...