flow_control: even more documentation

src/tools/flow_control.py

@@ -189,7 +189,9 @@ class Flow:
 if __name__ == "__main__":
     """
     This is the command line program to control the red-y flow control series.
-    Usage: ./flow_control.py [any number]
+    Usage: ./flow_control.py [FLOW]
+    
+    Several parameters are printed on every execution
 
     """
     conf = os.path.expanduser('~/.flow')