#autori=$(ls)
for i in *; do
  if [ -d "$i" ]; then
   echo "go in autore $i"
   cd "$i"
   #album=$(ls)
   for j in *; do
    if [ -d "$j" ]; then
     echo "go in album $j"
     cd "$j"   
     echo " removing m4a files"  
     rm -f *.m4a
     cd ..
    fi
   
  done
  cd ..
fi
done