cut4.sh

#!/bin/bash
#requires sejda-console to be in the path as 'sejda'
#https://github.com/torakiki/sejda/releases/download/v2.7/sejda-console-2.7-bin.zip

if [ "$1" == "-h" ]; then
  echo "Usage: pass the name of one file in the /in folder as a parameter. put all pdfs in an in/ folder"
  exit 0
fi

rm -r out/
mkdir out/
# calculate the pdf sizes
HEIGHT=$(mdls in/$1.pdf | grep PageHeight | perl -pe 's/.*= ([\d]+)\.\d*$/\1/')
WIDTH=$(mdls in/$1.pdf | grep PageWidth | perl -pe 's/.*= ([\d]+)\.\d*$/\1/')

echo "starting the calculations"
echo "height:$HEIGHT"
echo "width:$WIDTH"
MWIDTH=$(($WIDTH/2))
MHEIGHT=$(($HEIGHT/2))
echo "middle points: $MWIDTH and $MHEIGHT"
echo "starting sejda"
sejda crop --cropAreas \
	"[$MHEIGHT:0][$HEIGHT:$MWIDTH]"\
	"[$MHEIGHT:$MWIDTH][$HEIGHT:$WIDTH]"\
	"[0:0][$MHEIGHT:$MWIDTH]"\
	"[0:$MWIDTH][$MHEIGHT:$WIDTH]"\
	 --files "`pwd`/in/*.pdf" --output "`pwd`/out"