#!/usr/bin/perl

use strict;
use warnings;

die "Usage: $0 <file1> <file2>\n" unless @ARGV == 2;

my ($file2, %have)=pop;

while (<>) {
    chomp;
    $have{ (split /,/)[0] }=1;
}

@ARGV=$file2;
my %saw;
$\="\n";

while (<>) {
    chomp;
    local $_=(split /,/)[1];
    next if $saw{$_}++;
    print if $have{$_};
}

__END__