#!/usr/local/bin/perl
my $mydir="/path/dirname";
use strict;
opendir(DIR,$mydir) || die "Could not open $mydir: $!\n";
my %files=map {$_,1} readdir(DIR);
my %newfiles = "";
foreach my $file (keys %newfiles)
{
        unless (exists $oldfiles{$file}) new_file();
}