Duplicate a Database Using RMAN

In every piece of online documentaion I see the first step to duplicating
a DB with RMAN says that you must use the orapwd utility to create
a password file.

Ie:
http://www.oracle-base.com/articles/...singRMAN9i.php

While following each step in the arcticle above except creating the
orapwd file I was successful in creating the AUX DB.

Can somebody please explain why I would need the orapwd file? I am
obvisously missing something but not sure what.

Maybe you can provide an example as it pertains to the above mentioned article and show between what steps it would be accessed.

Thanks

You need orapwd file to be able to login "as sysdba" from an external (OS) account that belogs to the dba group.
:p

As per the document above, how come I did need to create an orapwd file when the directions say too. Can you please be a bit more specific.

FYI, I was logged into UNIX OS as user oracle and group dba

orapwd -as already pointed out by LKBrwn_DBA - allows for Operating System authentication so if you do not do as suggested in the note you are not going to have such a feature for your clonned database.

If not clear, please research O/S authentication.