Split multiple PDF files in linux using qpdf

split.sh

#!/bin/bash
function process() {
   echo "Processing $file"
   totpages=`qpdf --show-npages "$file"`
   echo "Processing $file : tot pages -> $totpages"
   numsplit=$((totpages/2))
   echo "Processing $file : tot splitted files -> $numsplit"
   for currsplit in $(seq 1 $numsplit);
   do
    echo "Exporting pages $(((currsplit-1)*2+1))-$((currsplit*2)) from $file"  
    qpdf "$file" --pages "$file" $(((currsplit-1)*2+1))-$((currsplit*2)) -- ./OUTPUT/"${file%.*}"-$(((currsplit-1)*2+1))-$((currsplit*2)).pdf
   done
}

find . -type f -name "*.pdf" -print0 | while IFS= read -r -d '' file;
do
  process $file
done