To prevent the prompting for a substitution variable value when executing a query:
B . Execute the SET VERIFY OFF command before executing the query: This command turns off the substitution variable prompting, which means that SQL*Plus will not prompt for a value and will use whatever value is currently set for that variable.
F . Use the DEFINE command before executing the query: By using the DEFINE command to set a value for the variable before the query execution, you ensure that SQL*Plus uses this predefined value instead of prompting for it.
Reference:
Oracle SQL*Plus User's Guide and Reference, which discusses how to manage substitution variables.