set serveroutput on
begin
   for i in 1..10
   loop
      dbms_output.put_line ('Zeile ' || i);
   end loop;

end;
/
_____________________________________________________________________

set serveroutput on
declare
   v_string        varchar2(10);
begin
   for i in 1..10
   loop
      v_string := v_string || '9';
      dbms_output.put_line (i || ' - String is ' || v_string);
   end loop;

end;
/