Am I overlooking something or could your sprintf statements be written much simpler like this?

    $res .= sprintf "%dw", $weeks   if $weeks;
    $res .= sprintf "%dd", $days    if $days;
    $res .= sprintf "%dh", $hours   if $hours;
    $res .= sprintf "%dm", $minutes if $minutes;
    $res .= sprintf '%ds', $seconds;
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Update: That was changed a little bit too much, as grinder correctly remarked ... nevertheless, my main concern were those ugly string interpolations, and I think this works:

 $res .= sprintf "%dw", $weeks   if                                $we
+eks;
 $res .= sprintf "%dd", $days    if                       $days or $we
+eks;
 $res .= sprintf "%dh", $hours   if             $hours or $days or $we
+eks;
 $res .= sprintf "%dm", $minutes if $minutes or $hours or $days or $we
+eks;
 $res .= sprintf '%ds', $seconds;
[download]

-- Hofmator