This should do what you want:

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1151834

use strict;
use warnings;

open my $FH1, '<', shift or die $!;

my %keys;
while (<$FH1>) {
    chomp;
    $keys{$_}++;
}

close $FH1;

open my $FH2, '<', shift or die $!;

while (<$FH2>) {
    chomp;
    my ($record, $key) = split ',', $_, 2;
    print "match: $key record: $record\n" if exists $keys{$key};
}

close $FH2;

[download]

Your code looks like something you've copied from somewhere without really understanding it. I'd advise against doing that: cargo cult code like that might be inefficient, might not actually do what you want, or it might even do damage to your system or data without you knowing it.

In reply to Re: comparing 2 columns by kikuchiyo
in thread comparing 2 columns by 2015_newbie

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.