Script which converts the 2-up PDF file into the single page PDF file

pdfunup.sh

#!/bin/sh

usage(){
    cat <<EOF
This script converts the 2-up PDF file into the single page PDF file.

For example, http://www.city.yokohama.lg.jp/kankyo/midoriup/jigyo/mori/guidebook.pdf
is a PDF file which consists of A3 16 pages, each A3 page contains 2
A4 pages.  In order to print the above PDF as a brochure, do the
following procedure.

(0) This script depends pdfinfo which is provided by poppler-utils 
    package and pdftk.  Install them before executing this script.
    
        sudo apt-get install poppler-utils pdftk

(1) Execute this script to split each A3 page into two A4 pages, as follows:

        sh pdfunup.sh input.pdf A4_pages.pdf

(2) Sort some broken ordered pages.

        pdftk A4_pages.pdf cat 2-32 1 output A4_sorted.pdf

(3) Riffle it, using https://github.com/ueokande/rifflepdf

        rifflepdf -o A4_riffled.pdf -m pdftk A4_sorted.pdf

(4) Print the above PDF file in 2-up style and double-sided
    printinting.

EOF
}

input=${1}
output=${2}
beginpage=${3}
endpage=${4}

if [ ! -f "${input}" -o -z "${output}" ]; then
    usage
    exit
fi
if [ -z "${beginpage}" ]; then
    beginpage=1
fi

dir=`mktemp -d unfold.XXXXXXXX`
rmdir(){
    rm -rf ${dir}
}
trap 'rmdir' INT TERM PIPE

maxpage=`pdfinfo ${input}|awk '/^Pages:/{print $2}'`
count=0
if [ ${beginpage} -gt 1 ]; then
    lastpage=`expr ${beginpage} - 1`
    for page in `seq 1 ${lastpage}`; do
	pagepdf=${dir}/sep_${count}.pdf
	count=`expr ${count} + 1`
	echo pdftk ${input} cat ${page} output ${pagepdf}
	pdftk ${input} cat ${page} output ${pagepdf}
    done
fi

if [ -z "${endpage}" ]; then
    lastpage=${maxpage}
else
    lastpage=`expr ${endpage} - 1`
fi
for page in `seq ${beginpage} ${lastpage}`; do
    pagepdf=${dir}/page_${page}.pdf
    leftpdf=${dir}/sep_${count}.pdf
    count=`expr ${count} + 1`
    rightpdf=${dir}/sep_${count}.pdf
    count=`expr ${count} + 1`

    echo pdftk ${input} cat ${page} output ${pagepdf}
    pdftk ${input} cat ${page} output ${pagepdf}

    # For more detail of these commands, see https://superuser.com/questions/191373/linux-based-tool-to-chop-pdfs-into-multiple-pages
    pagesize=`pdfinfo ${pagepdf}|awk '/^Page size:/{print $3,$5}'`
    height=`echo ${pagesize}|cut -f2 -d' '|cut -f1 -d.`
    width=`echo ${pagesize}|cut -f1 -d' '|cut -f1 -d.`
    if ( pdfinfo ${pagepdf} | egrep -q '^Page[[:space:]]+rot:[[:space:]]+90' ); then
	tmpvar=${height}
	height=${width}
	width=${tmpvar}
    fi
    height=`expr ${height} '*' 10`
    offset=`expr ${width} '/' 2`
    width=`expr ${width} '*' 5`
    echo gs -q -dBATCH -o ${leftpdf} -sDEVICE=pdfwrite -g${width}x${height} -c '<</PageOffset [0 0]>> setpagedevice' -f ${pagepdf}
    gs -q -dBATCH -o ${leftpdf} -sDEVICE=pdfwrite -g${width}x${height} -c '<</PageOffset [0 0]>> setpagedevice' -f ${pagepdf}
    echo gs -q -dBATCH -o ${rightpdf} -sDEVICE=pdfwrite -g${width}x${height} -c '<</PageOffset [-'${offset}' 0]>> setpagedevice' -f ${pagepdf}
    gs -q -dBATCH -o ${rightpdf} -sDEVICE=pdfwrite -g${width}x${height} -c '<</PageOffset [-'${offset}' 0]>> setpagedevice' -f ${pagepdf}
done

if [ ! -z "${endpage}" ]; then
    for page in `seq ${endpage} ${maxpage}`; do
	pagepdf=${dir}/sep_${count}.pdf
	count=`expr ${count} + 1`
	echo pdftk ${input} cat ${page} output ${pagepdf}
	pdftk ${input} cat ${page} output ${pagepdf}
    done
fi

count=`expr ${count} - 1`
for page in `seq 0 ${count}`; do
    echo gs -q -sOutputFile=${dir}/resize_${page}.pdf -sDEVICE=pdfwrite -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -dPDFFitPage ${dir}/sep_${page}.pdf
    gs -q -sOutputFile=${dir}/resize_${page}.pdf -sDEVICE=pdfwrite -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -dPDFFitPage ${dir}/sep_${page}.pdf
done
pdftk `seq 0 ${count}|xargs -n 1 printf "${dir}/resize_%d.pdf "` cat output ${output}

rmdir