+echo -n "$PRODUCT-$VERSION serial number: "
+
+case $# in
+ 1)
+ SERIAL="$1"
+ echo "$PRODUCT-$VERSION serial number: $SERIAL"
+ ;;
+ 0)
+ echo -n "$PRODUCT-$VERSION serial number: "
+ read SERIAL
+ ;;
+ *)
+ echo "Usage: $0 <serial-number>" 1>&2
+ exit 1;
+ ;;
+esac