package X;
sub A { " base class implementation" }
sub B { " base class implementation" }
1;

package Y;
@ISA (X);

# Let's use A() from the base class
sub B { "local implementation" }


##</code><code>##

sub Y::A {
   unless ($getopt{special_case}) {
      $self->SUPER::A();
      return;
   } 

   # do the stuff based on the command line arg if
   # the special case was chosen from the cmd line.
}