Identify gaps in logs

gistfile1.pl

#!/usr/bin/perl
use strict;
use warnings;
use autodie ':io';
use Time::Duration qw(duration);
use Date::Parse qw(str2time);

my $min_gap = shift || 3600;

my $prev;
while (my $line = <>) {
    my $ts = parse_date($line);
    if (defined $ts) {
        if (defined $prev) {
            my $delta = $ts - $prev;
            if ($delta >= $min_gap) {
                print "--- GAP: " . duration($delta) . " ---\n";
            }
        }
        $prev = $ts;
    }
    print $line;
}

sub parse_date {
    my $line = shift;
    $line =~ /^\[ ([^\[]+) \]/x or return;
    my $ts = str2time($1);
    return $ts;
}