Syntax of export command

I am looking at a script which has the following syntax for exp utility :
exp "/ as sysdba" owner=$SCHEMA log=$LOGFILE file=$DMPFILE consistent=y direct=y statistics=none

I am told this script runs when $LOGNAME="oracle" on a linux server. To the best of my knowledge, the syntax is : exp "username/password as sysdba" owner=$SCHEMA, etc etc. And I don't know how the command runs without being supplied username and password.

I am trying to export it to Windows.
If I use : exp "/ as sysdba" owner=$SCHEMA etc etc, I get an error. If I use : exp " as sysdba" owner=$SCHEMA etc etc, I am prompted for username and password.

So can the export utility be run on unix/linux without supplying username and password to it when a) logged in as 'oracle' and b) when logged in something else.
And can export utility be run on Windows without supplying username and password? Received on Mon Oct 08 2007 - 18:00:10 CDT