my %data;
open(LS,"find /tmp -type f -ls | awk '{ print %1,$5,$8,$9,$10 }' |") || die "cannont run find $!";
while (<LS>) {
  if (/(\d+) (\w+) (.+)/) {
    $size=$1;
    $user=$2;
    $date=$3;
    $data{$user}{"size"}+=$size;
    if (is_later_than($data{$user}{"date"},$date)) {
      $data{$user}{"date"}=$date;
    }
  }
}
foreach $user(sort(keys %data)) {
  print "$user used $data{$user}{"size"}, last accessed $data{$user}{"date"}\n";
}