Error E031
Message
[DBC-E031] %s: No valid ORACLE_HOME provided (try --orahome)
Explanation
A running Oracle instance has been detected, but no ORACLE_HOME is detected to use with the instance.
Potential cause: No entry in /etc/oratab or the permissions do not allow the user to read this file.
Solution:
Verify contents and permissions of the oratab file.