created a file named .bash_profile under the /home/oracle
First, without any line in the file, go to the terminal issue: su - oracle --> successfully switch to the oracle user environment
Now add, ORACLE_BASE=/u01/app/oracle export ORACLE_BASE go back to the terminal: su - oracle --> error: -bash: export : command not found
Worse, if I put these lines in the file: DISPLAY=0.0 export DISPLAY I can not even log in to the oracle user account.
Similarly, if I put DISPLAY=0.0 export DISPLAY +xhost in the /root I will not be able to log in as root.