sqlplus / as sysdba
SQL*Plus: Release X.X.X.X Production on Sun Feb 16 21:00:43 2014
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ERROR:
ORA-12547: TNS:lost contact
Enter user-name:
On one fine day if you encounter above error suddenly (without messing up the Database much, :-) )
You would like to see the $ORACLE_HOME/bin/oracle binary permission and ownership
Permission to $ORACLE_HOME/bin/oracle binary should be 6751 and permission will be <oracle_user>:<oracle_group>, something like this
chmod 6751 $ORACLE_HOME/bin/oracle
chown oracle:dba $ORACLE_HOME/bin/oracle
Above two commands should help start the database, just fine.
