split-scanned-book.sh

#!/bin/bash

# thanks to Ocaso Protal! http://stackoverflow.com/questions/14704274/how-to-write-shell-script-for-finding-number-of-pages-in-pdf
n_pages=$(pdfinfo $1 | grep Pages | awk '{print $2}');

page_width=$(pdfinfo $1 | grep "Page size" | awk '{print($3)}');
page_width=$(echo "$page_width/2" | bc);
odd_file="tmp-$1-odd.pdf";
even_file="tmp-$1-even.pdf";


# generating pdf with odd pages
pdfjam $1 --trim "0cm 0cm $(echo $page_width)px 0cm" --clip true --outfile $odd_file --no-tidy --quiet;

# generating pdf with even pages
pdfjam $1 --trim "$(echo $page_width)px 0cm 0cm 0cm" --clip true --outfile $even_file --no-tidy --quiet;

# mixing up both pdfs
pdfjam_arguments="";
for i in $(seq 1 ${n_pages}); do
    pdfjam_arguments+="$even_file $i $odd_file $i ";
done

# i know, i know, eval is evil, but... but... i can't find another way D:
eval "pdfjam $pdfjam_arguments --outfile fixed-$1 --quiet"; 

# removing temporal pdfs...
rm tmp-$1-even.pdf
rm tmp-$1-odd.pdf