SQL*Plus not showing headings when running query:

SQL*Plus do not show the heading of the columns when running query.Even when setting “set heading on” not changed anything

Result as below:

SQL> select instance_name,status from v$instance;
mydb          OPEN

Change file in below file:
$ORACLE_HOME/sqlplus/admin/glogin.sql, Basically SQL*Plus runs this file on startup.

Add these lines:
SET LINESIZE 150
SET PAGESIZE 0