correct protocol for Automator loop recursing through subfolders

sample.sh

# use Pass input: "to stdin", NOT "as arguments"
while read f ## NOT "for f in $@"
do
  # file processing code goes here
done

# Explanation: Apple doesn't document this, but "Pass input: as arguments" has a hard limit of 999 files/folders above which Automator
#              throws a "Run Shell Script" error; stdin does not have this limit but alters the way the passed array is referenced.