generates a list of a pdfs in local directory and subdirectory starting with Rechnung

find . -iname ‚Rechnung*.pdf‘ -newermt 20160101 -not -newermt 20170101 >/root/pdf-2016.txt

copys all files to a directory

for f in cat /root/pdf-2016.txt;
do cp -p $f /home/ubuntu/pdf-2016/;
done