#!D\perl\bin\perl.exe -w


use strict;

my (%dirlist, %loglist, @difference, $dir);
unless ($dir = $ARGV[0]) { die "Needs a directory.";}
$dir =~ s(\\+)(/)g;
unless (-d $dir) {die "This is not a valid directory. $!";}
my $logfile = "${dir}/mydirlog.txt";

opendir DIR, "$dir";
while ($_ = readdir(DIR)) {$dirlist{$_}++;}
closedir DIR;

if (-e $logfile) {
    open (OLDLOG, $logfile) or die "Cannot open existing log file.\n$!";
    while (<OLDLOG>) {chomp; $loglist{$_}++;}
    close OLDLOG;

    foreach my $dirName (keys %dirlist) {
        unless (defined $loglist{$dirName}) { push @difference, "$dirName";}
    }

    foreach my $logName (keys %loglist) {
        unless (defined $dirlist{$logName}) { push @difference, "$logName";}
    }
}

open LOG, "> $logfile";
foreach (keys %dirlist) { print LOG "$_\n"; }
close LOG;

print "@difference";