To see this implemented without any modules, you can look at the following code (look at my note at the end, though):

#!perl

use strict;
use warnings;

sub printDir {
   my $headDir = shift;     # get starting directory
   our $indent   = 3;       # indentation
   our $increase = 3;       # indentation steps
   sub recurseDir {
      my ($home, $dir) = @_;       # get home directory and current di
+rectory
      unless (-d "$home\\$dir") {  # if it is a file
         print " " x $indent . "$dir\n"; # just print its name
         return;
      }
      print " " x $indent . "[$dir]\n"; # it's a dir, so print its nam
+e fancily
      opendir(DIR, "$home\\$dir")       # let's have a look at the dir
+'s contents
         or die "Failed to open '$home\\$dir': $!\n";
      my @filelist = readdir DIR;       # get them
      closedir DIR;                     # close the handle
      $indent += $increase;             # increase indentation for nex
+t recursion level
      for (@filelist) {                 # iterate through dir contents
         next if ($_ eq '.' or $_ eq '..'); # ignore if . or ..
         recurseDir("$home\\$dir", $_);     # and recurse otherwise
      }
      $indent -= $increase;             # restore indentation
   }
   unless (-d "$headDir") {
      print " " x $indent . "$headDir\n";
      return;
   }
   print " " x $indent . "[$headDir]\n";
   opendir(DIR, $headDir) or die "Failed to open '$headDir': $!\n";
   my @filelist = readdir DIR;
   closedir DIR;
   $indent += $increase;
   for (@filelist) {
      next if ($_ eq '.' or $_ eq '..');
      recurseDir($headDir, $_);
   }
}

printDir 'C:\Dokumente';
[download]

In real life, however, (if it exists ;-) you should always use File::Find or a similar module to make your code more portable and easy to read. Furthermore ther are some traps, like links and such, which might render this simple solution useless. Conclusion: Always use File::Find or a similar module.
Hope this helped.
CombatSquirrel.

---

Entropy is the tendency of everything going to hell.