Modificato shell.sh

diff --git a/Filtering/shell.sh b/Filtering/shell.sh
index 9fb833a..cedd1b3 100755
--- a/Filtering/shell.sh
+++ b/Filtering/shell.sh
@@ -5,5 +5,9 @@ if [[ "$1" == "convert" ]]; then
   sox "$3".wav -e signed -b 16 "$3" channels 1 rate 44100
   rm "$3".wav
 else
+if [[ "$1" == "check" ]]; then
+    diff -s "$2" "$3"
+else
   aplay -r 44100 -f s16_le "$1"
 fi
+fi