$s=$t % 60; $t=($t-$s)/60; $m=$t % 60; $t=($t-$m)/60; $h=$t % 24; $d=($t-$h)/24; $out=sprintf "%03d:%02d:%02d:%02d\n", $d,$h,$m,$s; $out=~s/^0+:|00://g;