diff --git a/skratch.py b/skratch.py
index 8e4598e..8cbdd0f 100755
--- a/skratch.py
+++ b/skratch.py
@@ -89,6 +89,7 @@ def main():
 	
 	group.add_argument(
 		"-o", 
+		metavar="<file>",
 		help="open file", 
 		action="store")