Only 4 lines less? 
use strict;
use warnings;

my $INDENT=' 'x2;
my @aSorted=sort qw(/var/www/data/stuff
                    /var/www
                    /var/www/data/misc
                    /var/logs
                    /var/logs/data);
my $aLast=[];
foreach my $sPath (@aSorted) {
  chomp $sPath;
  my @aName  = split(m{/}, $sPath);
  for my $i (0..$#aName) {
    if (($#$aLast<$i) || ($aLast->[$i] ne $aName[$i])) {
      if ($i>1) { print '', $INDENT x ($i-1), '->'; }
      print $aName[$i], "\n";
    }
  }
  $aLast=\@aName;
}

[download]

outputs

var
  ->logs
    ->data
  ->www
    ->data
      ->misc
      ->stuff

[download]

By using the leading portions of the path as a hash key, the subscript separator variable, $; (see perlvar), you can preserve the exact ordering given by the OP. This also takes under 20 lines, excluding the strict and warnings declaration.

use strict;
use warnings;

my $INDENT=' 'x2;
my @aUnsorted= qw(/var/www/data/stuff
                /var/www
                /var/www/data/misc
                /var/logs
                /var/logs/data);
my %hVisited;
foreach my $sPath (@aUnsorted) {
  chomp $sPath;
  my @aName = split(m{/}, $sPath);
  for my $i (0..$#aName) {
    my $k=join('/',@aName[0..$i]);
    unless ($hVisited{$k}) {
      if ($i>1) { print '', $INDENT x ($i-1), '->'; };
      print $aName[$i], "\n";
      $hVisited{$k}=1;
    }
  }
}

[download]

outputs

var
  ->www
    ->data
      ->stuff
      ->misc
  ->logs
    ->data

[download]

For the OP, I don't know that language is the real winner here in getting the volume of code down. Understanding the nature of the problem itself is far more important. PHP also has a split function and str-repeat takes the place of Perl's x operator, so this code could be translated virtually as is to PHP.

Best, beth

Update: ikegami is right, I'm not actually using $; but rather the path subsegments as the hash key. See strike out above for correction.

In reply to Re^2: directory listing to array tree by ELISHEVA
in thread directory listing to array tree by Anonymous Monk

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