-- FAQ.SQL
insert into dept values (0, 'Little', 'Foot');

prompt <C> to 'commit', <R> to 'rollback'
prompt
accept odg prompt 'What will you do? ';

set termout off;
set verify off;
set heading off;
set pause off;
set echo off;
column action newline;
spool todo.sql

select decode (upper('&&odg'), 'C', 'commit;', 'rollback;') action
from dual;

spool off;
set termout on;
@todo

undefine odg;

SQL> select * From dept;

        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON

SQL> @faq

1 row created.

<C> to 'commit', <R> to 'rollback'

What will you do? r

Rollback complete.

SQL> select * From dept;

        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON

SQL> @faq

1 row created.

<C> to 'commit', <R> to 'rollback'

What will you do? c

Commit complete.

SQL> select * From dept;

        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON
         0 Little         Foot

SQL>