#!/usr/bin/perl

use strict;
use warnings;

my @path = qw(
    /abc/def/1/2/3/4/5/6/7/8
    /abc
    /abc/1/2/a/b/c
    /abc/2
    /tmp/1/2/a/../b/c
    /abc/def/1/2/a/b/c
    abc/def/../../john/Desktop/work
    abc/../john/Desktop/work
    ../john/Desktop/work
    /abc!def/1/2/a/b/c/.
    /abc/def
    /abc-def/1/2/a/b
    /./home
    ./abcdef/1/2/a/b/c
    /tmp
    /usr/a
);

foreach (@path)
{
  # Let's get rid of . and ..
  $_ =~ s!^\./!!;
  $_ =~ s!^/\./!/!;
  $_ =~ s!/\.$!/!;
  $_ =~ s!/\./$!/!;
  $_ =~ s!/\./!/!g;
  while ($_ =~ s![^/.]+/[.]{2}/!!) {}

  # Next, we change every "/" to "\xFF"
  # and insert the path depth encoded as a
  # character in front of the path.
  my $test = substr($_, 1);
  my $depth = $test =~ tr|/|/|;
  $_ =~ tr|/|\xff|;
  $_ = chr($depth) . $_;
}

@path = sort @path;    # Sort list

foreach (@path)
{
  $_ = substr($_, 1);
  $_ =~ tr|\xff|/|;    # Undo changes
  
  print "\n $_";       # Print sorted list
}