Where to set?
 

In the win environment we were using registry to set some settings for our oracle home like nls_date_format=....

But try to find a way to do the same in RH9?

Oracle (the entire Sun products!!!) are really badly made. I mean, Sun keep trying to invent standard, instead of using existing standard (as result, none of their apps are intuitive and some things just don't make sense).
In Linux, setting *should* be in ~/.name_of_the_apps. So if your user is bob, setting for oracle should be in /home/bob/.oracle (or sometime in /etc/ since oracle is mostly server application).
But don't expect too much about it, I guess Sun put this somewhere else just to be "different".

I don't think Oracle has anything to do with Sun????

is Oracle a sub-corporation of Sun? I tought it was. eeeeh maybe I'm damn wrong sorry if I am. Anyways, I tried Oracle linux once and I wasn't surprised, their installer is buggy, there is very low support and some standardisation problem.
As stated, config files should be in ~/.oracle (or similar location) but
don't be surprise if it is not.

Oracle is totally independent and worlds no 1 RDBMS. www.oracle.com
May be when you had touched oracle it was buggy but now they have improved a lot. Sun makes servers and they have their OS Sun Solaris.

yeah I know they make their own OS and build server (my friend own a Sparc with Solaris on it, very cool) but they also develop some "things". As example, sun made NFS, Java, Star Office... I dunno why I was thinking Oracle was owned by them, I suppose my brain got a bug here, LOL. They made some goods things, but they try to play Micro$oft, they develop their own standard and so don't follow existing standardisation, so I find most of their products... strange.