If THEN or ELSE is not followed by a continuation character or by a command on the same line, the result is a null command. A semicolon after the THEN or ELSE keyword also results in a null command. A null command specifies that no action is taken if the IF clause is satisfied (a null THEN command) or if the IF clause is not satisfied (a null ELSE command).

IF ... THEN              or          IF ... THEN;
       ELSE ...                             ELSE ...

IF ... THEN ...          or          IF ... THEN ...
       ELSE                                 ELSE;