my $i = 0;

 while ( $i != -1 ) {
  $i = index( $text, "ll", $i );

  if ( $i != -1 ) {
    print $i, "\n";
    $i = $i + 1;
  }
}

##</code><code>##

my $i = 0;

print $i++, "\n" while ( ( $i = index( $text, "ll", $i )) != -1 );