$search = $top->Entry ('-width' => 20,
                           ) ->pack('-side' => 'left');

    $search->bind('<KeyPress-Return>', \&search);



sub search
   {
   SEARCH_GET:

     my ($search_pattern , $string   );
      $search_pattern = $search->get();

     print "Pattern entered into Search-box is:  $search_pattern\n   ";

      (goto SEARCH_GET) if (! (defined $search_pattern)  ); # if <RET> is entered by itself, then ignore it...

      if ( $search_pattern =~ /^([\w\s\-\:\_\d]+)$/   )  ## CHECK $search_pattern and untaint:
	{                                              ## make sure it only contains \w, '-' , ':' , '_' , and digits
          $string = $1;                                ## DON'T forget 's -- space between prog and $arg

	  print "\$string is untainted; \$string = $string \n ";
	}
        else
           {
             print "OOPS! data is tainted. TRY AGAIN...\n  ";

           }



                          .
                          .
                          .

   }