The Tor Browser / file revision

 #!env perl

 # This Source Code Form is subject to the terms of the Mozilla Public

 # License, v. 2.0. If a copy of the MPL was not distributed with this

 # file, You can obtain one at http://mozilla.org/MPL/2.0/.

 use File::Spec::Unix;

 use strict;

 print "Usage: $0 dest_path start_path\n" if ($#ARGV+1 != 2);

 my $finish = my_canonpath(shift);

 my $start = my_canonpath(shift);

 my $res = File::Spec::Unix->abs2rel($finish, $start);

 #print STDERR "abs2rel($finish,$start) = $res\n";

 print "$res\n";

 sub my_canonpath($) {

     my ($file) = @_;

     my (@inlist, @outlist, $dir);

     # Do what File::Spec::Unix->no_upwards should do

     my @inlist = split(/\//, File::Spec::Unix->canonpath($file));

     foreach $dir (@inlist) {

 	if ($dir eq '..') {

 	    pop @outlist;

 	} else {

 	    push @outlist, $dir;

 	}

     }

     $file = join '/',@outlist;

     return $file;

 }