SQL> set serveroutput on
SQL> begin
2 dbms_output.put_line('------------output------------');
3 dbms_output.put_line('end--------------');
4 end;
5 /

------------output------------
end--------------

PL/SQL procedure successfully completed


SQL> begin
2 dbms_output.enable(100000);
3 dbms_output.put_line('test');
4 end;
5 /

test

PL/SQL procedure successfully completed