Crop pdfs with GhostScript

ghostscript-pdf-crop.sh

#!/usr/bin/env bash

set -euo pipefail
origdir=$(pwd)
tmpdir=$(mktemp -d)
echo "tmpdir: $tmpdir"
read -r width height < <(pdfinfo $1 | grep "Page size:" | sed 's/[a-zA-Z: ]*\([0-9]\+\)[x ]*\([0-9]\+\).*/\1 \2/')
npages=$(pdfinfo $1 | grep "Pages:" | sed 's/Pages: \+\([0-9]\+\).*/\1/')
echo "page count: $npages"
echo "(width, height) = ($width, $height)"

cp $1 $tmpdir/orig.pdf
cd $tmpdir

margleft=$2
margtop=$3
margright=$4
margbot=$5

left=$margleft
top=$((height-margtop))
right=$((width-margright))
bot=$margbot

echo -e "bbox:\n  left: $left\n  right: $right\n  bot: $bot\n  top: $top"

# Remove any cropbox already present
sed -i 's/CropBox/cROPbOX/g' orig.pdf

getTime() {
  date +%s.%N | sed 's/[^0-9]//'
} 

startTime=$(getTime)

elapsed() {
  local timeNow=$(getTime)
  echo $((timeNow-startTime))
}

case "$6" in
  end)
    pageExtents=''
    ;;
  *)
    pageExtents="-dLastPage=$6"
    ;;
esac


# Crop
echo "cropping"
ls
gs $pageExtents -o cropped.pdf -sDEVICE=pdfwrite -dNOPAUSE -dBATCH -c "[/CropBox [$left $bot $right $top]" -c " /PAGES pdfmark" -f orig.pdf \
  | grep --line-buffered '^Page' \
  | sed --unbuffered 's/[^0-9]//g' \
  | sed --unbuffered "s/.*/echo \"& (\$(( ( \$(date +%s.%N | sed 's:[^0-9]::') - $startTime )\/1000000000 ))s elapsed, estimated \$(( ( (\$(date +%s.%N | sed 's:[^0-9]::') - $startTime)\/100000000) * ($npages - &) \/ (& * 10) ))s remaining)\"/ep" \
  | stdbuf -o0 tr '\n' '\r'
echo ""

  # | sed --unbuffered "s/Page \([0-9]\+\)/converted page \1 of $npages/" \
mv cropped.pdf $origdir/crop-$1
ls -l $origdir/crop-$1