'-validatecommand'  => sub {$_[1] =~/[\w:-]+/ ;} ,

##</code><code>##

'-invalidcommand' => sub {
                          return if $_[1] =~/^[[:cntrl:]] ;
                          $top -> bell;
                         }

##</code><code>##

'-invalidcommand' => sub {
                          $top -> bell if $_[1] =~/^[[:cntrl:]] ;
                         }