You can set the ORACLE_SID and export it for all users in the /etc/profile file (using bourne or korn shell). If you have multiple Oracle instances on one box you can use the .profile files of individual users to set this environment variable for each one. You should also run the oraenv script after setting the ORACLE_SID.

There is an Oracle-supplied script in $ORACLE_HOME/bin called dbstart, which is designed to be called at system startup. Unfortunately this does not include listener control commands so you should create a shell script which calls dbstart and then the lsnrctl command. There is a similar script called dbshut for automatic shutdown.

Hope this helps

Gerry Miller