Check if PostgreSQL dump is valid
The command you show generates a text backup file.  You can use "head" or "less" on it to verify that it looks like a PostgreSQL text backup file, same as mysql.  I'd also run "tail", just to make sure it didn't get truncated.  It should end with a sign-off like:

--
-- PostgreSQL database dump complete
--

--
-- PostgreSQL database cluster dump complete
--


Of course to be really sure, you would just set up a dummy database server, and restore it.