Running Oracle SQLPlus with Linux

Environment :
Linux kernel : 2.6.18-194.26.1.el5 (uname -r)
Distro : CentOS release 5.5 (Final) (cat /etc/issue)
Oracle : Oracle Database 10g Express Edition Release 10.2.0.1.0 – Production

If you get the following annoying message :

[me@somewhere]$sqlplus
Error 6 initializing SQL*Plus
Message file sp1.msb not found
SP2-0750: You may need to set ORACLE_HOME to your Oracle software directory

then do not waste your time installing patches, changing files and folders permissions etc.
The problem resides in the environment variables settings.
You need to set up the ORACLE_HOME variable correctly.

If after setting that ORACLE_HOME environment variable correctly, you get this other annoying message :

[me@somewhere ~]# sqlplus

SQL*Plus: Release 10.2.0.1.0 - Production on Sat Jul 23 17:48:03 2011

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

Enter user-name: SYSTEM
Enter password: 
ERROR:
ORA-12162: TNS:net service name is incorrectly specified

then you need to set up other environment variables (ORACLE_SID, NLS_LANG, LD_LIBRARY_PATH).

Fortunately Oracle provides a script that contains all these environment variables with the right values.
This script is called oracle_env.sh and is located here :
/usr/lib/oracle/xe/app/oracle/product/10.2.0/server/bin

All you need to do is insert these lines in your .bash_profile and you’re ready to connect to SQLPlus in no time !