Check the syntax of rman commands - oracle database script

--- check the syntax of RMAN commands interactively without actually executing the commands  $ rman checksyntax  Recovery Manager: Release 12.1.0.2.0 - Production on Sun Jan 29 12:04:24 2017  Copyright (c) 1982, 2014, Oracle and/or its affiliates. All rights reserved.  -- Now put the command for checking syntax  RMAN> backup database;  The command has no syntax errors