added usage if no input

profile.py

@@ -142,7 +142,11 @@ if __name__== "__main__":
     parser.add_argument('outfile', default = None, nargs='*',
                         help='the .out file to process.')
     args = parser.parse_args()
-    from pprint import pprint
+    
+    if args.outfile == []:
+        parser.print_usage()
+        exit(-1)
 
+    from pprint import pprint
     for inputfile in args.outfile:
         pprint(profile(inputfile))