#! /usr/bin/perl -w

use strict;
use warnings;
use Digest::SHA1;

sub get_filedigest {
    my ($filename) = @_;
    open(FILE, $filename);
    my $ctx = Digest::SHA1->new;
    $ctx->addfile(*FILE);
    my $digest = $ctx->hexdigest;
    close(FILE);
    return $digest;
}

sub get_filesize {
    my ($filename) = @_;
    my @s = stat($filename);
    return $s[7];
}

my $dir = opendir DIR,'.';
my %digest_table;

foreach my $f (readdir(DIR)) {
    if ($f =~ /^(\.|\.\.)$/) {
	next;
    }
    my $d = get_filedigest($f);
    if (exists $digest_table{$d}) {
	unlink $f;
    }
    $digest_table{$d} = $f;
}