update_pdf_meta.sh

#!/bin/bash
SAVEIFS=$IFS
IFS=$(echo -en "\n\b")

pdftk_path="/usr/local/bin/pdftk"  # full path to pdftk binary
pdf_infokeys="~/pdf-infokeys"      # full path to file containing new metadata
pdf_search_path="/var/www/html"    # path to search for pdf files
pdf_temp_path="/tmp"               # temporary directory


for i in $( find $pdf_search_path -type f -name "*.pdf" ); do
  cp $i $pdf_temp_path/temp.pdf
  $pdftk_path $pdf_temp_path/temp.pdf update_info $pdf_infokeys output $i
  rm $pdf_temp_path/temp.pdf
done

IFS=$SAVEIFS