How do I exit a script in SQLPlus when an error occurs and return to the SQLPlus prompt, without disconnecting or exiting SQLPlus?

It's not possible.

SQLPlus doesn't provide that level of control over the execution of a script.

Obviously, you'd need to AVOID using the WHENEVER SQLERROR EXIT ... command.

It's possible to gain conditional control over which SQL statements do or do not get executed as a result of raised exceptions (errors) using PL/SQL. But that doesn't address SQLPlus commands (which cannot be executed from within a PL/SQL block.)

DECLARE
  lb_continue BOOLEAN;
BEGIN
  lb_continue := TRUE;
  BEGIN 

    sql statement

  EXCEPTION
    WHEN OTHERS THEN
      lb_continue = FALSE;
  END;
  IF lb_continue THEN
  BEGIN

    sql statements

  EXCEPTION
    WHEN OTHERS THEN
      lb_continue := FALSE;
  END; 
END;

Of course, that approach has it's own limitations and issues. Any DDL statements would need to be called dynamically; the easiest way to do that is an EXECUTE IMMEDIATE statement.

The biggest issue (in your case) is that it's not possible to execute SQLPlus commands from inside a PL/SQL block.

You can't exit the script and stay in SQL*Plus, but you can stop executing things. It isn't pretty, but assuming you can modify the script to add the control flow then you can just about do this with bind variable.

set serveroutput on

var flag char;
exec :flag := 'Y';

begin
    if :flag != 'Y' then
        raise program_error;
    end if;
    dbms_output.put_line('Doing some work');
    /* Check for some error condition */
    if 0 != 1 then
        raise program_error;
    end if;
    /* Only reach this if earlier statements didn't fail
     * but could wrap in another flag check if needed */
    dbms_output.put_line('Doing some more work');
    exception
        when program_error then
            dbms_output.put_line(sqlerrm);
            :flag := 'N';
        when others then
            /* Real exception handling, obviously */
            dbms_output.put_line(sqlerrm);    
            :flag := 'N';
end;
/

-- DML only does anything if flag stayed Y
select sysdate from dual
where :flag = 'Y';

-- Optional status message at the end of the script, for DBA info
set feedback off
set head off
select 'Something went wrong' from dual where :flag != 'Y';
set feedback on
set head on

When executed:

SQL> @script

PL/SQL procedure successfully completed.

Doing some work
ORA-06501: PL/SQL: program error

PL/SQL procedure successfully completed.


no rows selected


Something went wrong
SQL> 

Any PL/SQL blocks in the script can check the flag status at the start, and raise program_error (just as a handy pre-defined exception) to jump back out. Anything that errors inside a PL/SQL block can update the bind variable flag, either directly or in an exception handler. And any non-PL/SQL DML can have an additional where clause to check the flag status, so if it's been set to N by the time that statement is reached, no work is done. (For an insert I guess that would mean not using the values form).

What this can't do is deal with any errors from plain SQL statements, but I'm not sure if that's an issue. If it is then those might need to be changed to dynamic SQL inside a PL/SQL block.

I know its old, but these two instructions at the very begining of the SQL script do the work:

WHENEVER SQLERROR EXIT FAILURE ROLLBACK

WHENEVER OSERROR EXIT FAILURE ROLLBACK