my $log1 = '/var/log/httpd/access_log';
my $log2 = '/var/log/httpd/access_log.1';
my %hash;
open FH1, $log1 or die $!;
open FH2, $log2 or die $!;
$hash{$_}++ while <FH1>;
$hash{$_}++ while <FH2>;
close FH1;
close FH2;
for (keys %hash) {
    print if $hash{$_} > 1;
}