convert shebang lines: python -> python3
diff --git a/Demo/scripts/lpwatch.py b/Demo/scripts/lpwatch.py
index 90b3ecf..01d9fea 100755
--- a/Demo/scripts/lpwatch.py
+++ b/Demo/scripts/lpwatch.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 # Watch line printer queue(s).
 # Intended for BSD 4.3 lpq.