There are a few ways of doing this, but this is the one I did most recently and now I know how to do it, it's easy enough. My assumptions for this procedure are:
Change the Oracle SID in this file to the SID of your new instance (Click here for help with vi).useradd newuser passwd newuser cp /home/oracle/.bash_profile /home/newuser/.bash_profile. vi /home/newuser/.bash_profile
You should now be newuser. In X Window, run dbassist (found in $ORACLE_HOME/bin) and follow your normal database creation procedure. Make sure you note the location of any datafiles, control files and redo logs. When you've finished, save to a script and exit X Window.su chmod 777 $ORACLE_BASE/admin chmod 777 $ORACLE_HOME/dbs chmod 777 $ORACLE_BASE/oradata chmod 777 /etc/oratab exit
As root do a chmod 777 on the directories that your datafiles, control files and redo logs are in. Also
chown oracle:dba $ORACLE_HOME/dbs/orapwnewSID