3 Ways to Log In Through Sqlplus as ‘sysdba’

1.If you are a member of DBA group on the Linux/Unix OS level:

sqlplus '/ as sysdba'


2.Or you can first log on as ‘nolog’

sqlplus /nolog

And then

SQL>connect / as sysdba


3. Directly connect to Oracle instance as sysdba

sqlplus 'sys as sysdba'

You’ll be prompted to type in the password and all will be OK.