foreach (@in) {
  my ($count, $file) = split;

  $file =~ s/^$in_prefix//;

  my ($campaign, $month, $fname) = split /\//, $file;

  $_ = { campaign => $campaign,
         month => $month,
         file => $fname,
         count => $count,
         sort => "$campaign:$month:$file" };
}

##</code><code>##

my @files = map {
  my ($count, $file) = split;

  $file =~ s/^$in_prefix//;

  my ($campaign, $month, $fname) = split /\//, $file;

  { campaign => $campaign,
    month => $month,
    file => $fname,
    count => $count,
    sort => "$campaign:$month:$file" };
} @in;