extract mp3 fix

tetras_extraction/script/extract_mp3.sh

@@ -20,6 +20,8 @@ while [ -n "$1" ]; do
 	shift
 done
 
+echo $input_file
+
 if [ -z "$input_file" ]; then
 	echo "Usage: $0 [-y|--yes-overwrite] [-o|--output-dir <dir>] <file>"
 	exit 1