#!/usr/local/bin/perl -w
use strict;
use warnings;
use DateTime::Format::Strptime;
my $Strp = new DateTime::Format::Strptime(pattern     => '%Y-%b-%d %T',);
my $infile = 'logfile.2008-02-25.log';
my $outfile = 'report-2008-02-25.txt';
my($fh_out, $fh);
my %lookup;
my $channel = 'two';
my $time_delta = 3600;  # seconds = 1 hour
open($fh_out, '>', $outfile) or die "Could not open outfile: $!";
# open($fh, '<', $infile) or die "Could not open logfile: $!";
while (<DATA>) {
    next unless /$channel/;
    $_ =~ m/^(.*) UTC.*refs = (\d+)$/;
    my $dt = $Strp->parse_datetime($1);
    my $timestamp = $dt->epoch();
    my $refs = $2;
    if ( defined($lookup{$refs}) && $lookup{$refs} + $time_delta <= $timestamp ) {
        print $fh_out "REFS $refs: occurrences at " . $lookup{$refs} . "and $timestamp \n";
        print "REFS $refs: occurrences at " . $lookup{$refs} . " and $timestamp \n";
    }
    $lookup{$refs} = $timestamp;
}
close $fh_out;
#close $fh;

##</code><code>##

Name "main::DATA" used only once: possible typo at a3.pl line 24.
readline() on unopened filehandle DATA at a3.pl line 24.

##</code><code>##

2007-Nov-07 00:00:00 UTC (GMT +0000) - Poll: channel = ONE, ref =
2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = THREE, ref =
2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:04 UTC (GMT +0000) - Poll: channel = TWO, ref =