Split a 2x2 "poster" pdf

pdf-un-poster4.sh

#!/bin/bash

function usage() {
    echo "Usage:"
    echo "  pdf-un-poster4 {in.pdf} [out.pdf]"
}

if [ -z "$1" ]; then
   usage
   exit 1
fi

INPUT=$1
OUTPUT=$2

if [ -z "$2" ]; then
    OUTPUT=out.pdf
fi

TMP=$(mktemp)
rm $TMP

echo "[+] Splitting into pieces"
mutool poster -x 2 -y 2 "${INPUT}" "${TMP}.pdf"

echo "[+] Separating out pieces"
pdftk A="${TMP}.pdf" cat A1-endeven output "${TMP}-A.pdf"
pdftk A="${TMP}.pdf" cat A1-endodd output "${TMP}-B.pdf"
rm "${TMP}.pdf"

pdftk A="${TMP}-A.pdf" cat A1-endeven output "${TMP}-a1.pdf"
pdftk A="${TMP}-A.pdf" cat A1-endodd output "${TMP}-a2.pdf"
pdftk A="${TMP}-B.pdf" cat A1-endeven output "${TMP}-b1.pdf"
pdftk A="${TMP}-B.pdf" cat A1-endodd output "${TMP}-b2.pdf"
rm "${TMP}-A.pdf" "${TMP}-B.pdf"

echo "[+] Reorganizing and merging"
pdftk A="${TMP}-a1.pdf" \
      B="${TMP}-a2.pdf" \
      C="${TMP}-b1.pdf" \
      D="${TMP}-b2.pdf" \
      shuffle B A D C output "${TMP}.pdf"
rm "${TMP}-a1.pdf" "${TMP}-a2.pdf" "${TMP}-b1.pdf" "${TMP}-b2.pdf"

echo "[+] Magic cropping"
pdfcrop "${TMP}.pdf" "${OUTPUT}" >/dev/null 2>/dev/null
rm "${TMP}.pdf"

echo "[+] Done"