Sql*plus always returns exit code 0?

You have to explicitly tell sqlplus to do that, in your script. Basically, there are two statements that you can use:

• WHENEVER SQLERROR EXIT SQL.SQLCODE
• WHENEVER OSERROR EXIT

For example:

WHENEVER SQLERROR EXIT SQL.SQLCODE
begin
  SELECT COLUMN_DOES_NOT_EXIST FROM DUAL;
END;
/

And for OS errors:

WHENEVER OSERROR EXIT FAILURE
START no_such_file

For more information, see this and that.

Hope it helps. Good Luck!

Vlad's is the answer I'd use. To augment his, however, I try to use an explicit EXIT statement if I really need that return status. For example

column status_for_exit new_value exitcode noprint
select status_computation (parm, parm) as status_for_exit from dual;

exit &exitcode;

The best action might a combination of the other ideas on this page and the ideas at

Help with SQLPLUS please? How to make SQLPLUS startup with DEFINE `OFF` initially?

Make a login.sql file, or edit the global one to have

WHENEVER OSERROR EXIT FAILURE
WHENEVER SQLERROR EXIT SQL.SQLCODE

inside it. Then, if the file doesn't exist, it will error out. If a line fails, it will error out.

However, keep in mind that as the docs say at : https://docs.oracle.com/cd/E11882_01/server.112/e16604/ch_twelve052.htm#SQPUG135 that certain commands still will not error out as you might expect.