Using SQL*Plus: the Oracle Interface

SQL*Plus, the Oracle interface, enables users to manipulate SQL commands and PL/SQL blocks.

help [ topic ] | help
HELP displays information on the commands of SQL*Plus, SQL, and PL/SQL. For example, the following command displays help on SELECT, SET commands, and SET operator. 
    SQL> help se
help index
List SQL*Plus, PL/SQL, and SQL commands.

list [ *|n [m|last] ] or n
LIST displays one or more lines of the SQL buffer. 
   SQL> list
     1  select * from customers
     2*   where name = 'Pokemon';
change /old/new
Use CHANGE to replace the first occurrence of the specified text on the current line of the buffer with the new specified text. 
   SQL> 1
     1* select * from customers
   SQL> c /customers/agents
     1* select * from agents
del [ *|n [m|last] ]
Deletes the current line, or one or more lines of the buffer. DEL makes the following line of the buffer the current line.

i [ new line ]
Inserts a new line or several lines of text after current line in buffer. 
   SQL> i where SSN = '123456789'