find artwork image and add to '*.m4a' files

add-artwork-to-m4a.sh

## this script depends on 'mp4art', one part of 'mp4v2'.
# brew install mp4v2
## if you need to remove artworks first,
# find . -type f -name '*.m4a' -print0 | xargs -0 mp4art --remove

## find local artwork image file and add to '*.m4a' files
artwork=`find . -type f \( -name '*.png' -o -name '*.jpg' -o -name '*.jpeg' \) -print | head -1`;
if [ -e "$artwork" ]; then find . -type f -name '*.m4a' -print0 | xargs -0 mp4art --add "$artwork" ; fi