Oracle not available error with Oracle XE 11.2.0-1.0 I have downloaded Oracle XE 11.2.0-1.0 and installed it on a CentOS 6.3 virtual machine with 1.5GB memory and 3GB of swap.

SYS and SYSTEM set to have password 123456. I have set ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe/ and ORACLE_SID=XE.

I can connect to this database with SQL Developer with the SYSTEM user. But when I want to connect with sqlplus it says:

ERROR.
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux-x86_64 Error: 2: No such file or directory
Process ID: 0
Session ID: 0 Serial number: 0


ps -fe | grep pmon shows this:

oracle    1164    1    0    11:26    ?    00:00:00    xe_pmon_XE


I have logged in as root user and I just type sqlplus with no arguments then it asks for user name and password.

Can anyone help?
I have removed the trailing / from ORACLE_HOME and it solved my problem.