ORA-28009: connection to sys should be as sysdba or sysoper

ORA-28009: connection to sys should be as sysdba or sysoper

Cause: connect sys/ is no longer a valid syntax

Action: Try connect sys/ as sysdba or connect sys/ as sysoper

ORA-28009: "connection to sys should be as sysdba or sysoper":

This occurs from Oracle 9i onwards if you try to connect as user SYS just by specifying username/password.

Instead you must connect 'as sysdba':

sqlplus "sys/sys@tnsname.world as sysdba"

Note the quotes if it's on a Unix command line, which are necessary to ensure that the connection string is all one argument.