Here is the command to connect to Oracle XE 11.2 (Express Edition) in SQL/Plus editor:
SQL> connect system/system@XE
In Command line you can use this command:
1. Change to ‘oracle’ user : su – oracle
2. Set Environment variables:
3. Then issue following command at shell prompt:
[localhost@m114116 ~]$ sqlplus system/system@XE
SQL*Plus: Release 188.8.131.52.0 Production on Mon Nov 7 07:11:04 2016
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Oracle Database 11g Express Edition Release 184.108.40.206.0 – 64bit Production
Note that here my password is ‘system’ which can differ from your installation.