SQLPLUS COMMAND LINE some set commands

 set sqlprompt "_user '@' _connect_identifier > "

[oracle@pm admin]$ cat $ORACLE_HOME/sqlplus/admin/glogin.sql
--
-- Copyright (c) 1988, 2005, Oracle.  All Rights Reserved.
--
-- NAME
--   glogin.sql
--
-- DESCRIPTION
--   SQL*Plus global login "site profile" file
--
--   Add any SQL*Plus commands here that are to be executed when a
--   user starts SQL*Plus, or uses the SQL*Plus CONNECT command.
--
-- USAGE
--   This script is automatically run
set lines 400;
set timing on;
set time on;
-- added by kayyum
set sqlprompt "_user '@' _connect_identifier > "
[oracle@pm admin]$
[oracle@pm admin]$
[oracle@pm admin]$ sq
SQL*Plus: Release 21.0.0.0.0 - Production on Wed Sep 6 18:41:04 2023
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle.  All rights reserved.

Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
18:41:04 SYS @ sakri >

SET AUTOTRACE ON;

SELECT * FROM employees;

SET SERVEROUTPUT ON;

BEGIN

  DBMS_OUTPUT.PUT_LINE('Hello, World!');

END;

/

SET LINESIZE 100;

SELECT employee_id, first_name, last_name FROM employees;

SET PAGESIZE 25;

SELECT * FROM products;

SET FEEDBACK OFF;

SELECT * FROM customers;

SET VERIFY OFF;

SELECT '&variable_name' FROM dual;

SET HEADING OFF;

SELECT department_name FROM departments;

SET NULL "N/A";

SELECT phone_number FROM employees WHERE employee_id = 9999;

SET SQLFORMAT CSV;

SELECT * FROM products;

SET TIMING ON;

SELECT * FROM orders;

SET TRANSACTION ISOLATION LEVEL READ COMMITTED;

-- Your SQL statements here

COMMIT;

SET ECHO ON;

SELECT * FROM employees;

SET TERMOUT OFF;

SELECT * FROM customers;

SQL> SET TIMING ON;

elapsed time 00:01:00 

to see time also 

SQL> set time on;

11:00:00 SQL> --- this way we can see---

to set col size :-

col column_name for a<size>;

example: 

SQL> col student_id for a20;

to clear col size:-

clear column;

SQL> clear column;

+++++++++++++++++++++ Auto format SQLPLUS CONSOLE COLUMNS +++++++++

-- Generate COLUMN commands for all columns in a table

SELECT 'COLUMN ' || column_name || ' FORMAT ' ||

  CASE

    WHEN data_type = 'NUMBER' THEN '999999'

    WHEN data_type = 'DATE' THEN 'DATE ''YYYY-MM-DD'''

    ELSE 'A' || data_length

  END || ';'

FROM user_tab_columns

WHERE table_name = upper('&YOUR_TABLE_NAME');