SYS password change in Oracle 12cR2 and 18c:

Oracle 12cR2 own wards,need to configure password file to change SYS account password.

Following error will be thrown while attempt to change the SYS password:

SQL> alter user sys identified by welcome ;

alter user sys identified by welcome
*
ERROR at line 1:
ORA-01994: Password file missing or disabled

Solution:

1. Set parameter in parameter file:

remote_login_passwordfile=exclusive

2.Create a password file:

orapwd file=orapwSID password=welcome1 entries=3

3.verification query:
col username for a10
select username,sysdba,sysoper from v$pwfile_users;

4. Now again change password:

SQL> alter user sys identified by welcome1 ;

5.Remove or rename the password file later.

6.Change parameter back to remote_login_passwordfile=none and restart the database.