Mine

#! /usr/bin/perl

use Modern::Perl;
use Time::ParseDate;

my $DEBUG;
#$DEBUG++;
sub debug { say @_ if $DEBUG };

my ($time, @command) = @ARGV;
debug "$time\t@command"; 

my $futuretime = parsedate($time,	TIMEFIRST => 1,
									PREFER_FUTURE => 1);

debug "future time is\n\t$futuretime\ntime is ", time;

my $seconds_until = abs($futuretime - time());

debug "$seconds_until until"; #DEBUG

countdown($seconds_until);
sub readable
{
	my ($seconds_pristine) = @_;
	my $seconds = $seconds_pristine % 60;
	my $minutes_pristine = $seconds_pristine/60;
	my $minutes = $minutes_pristine % 60;
	my $hours = int($minutes_pristine / 60);
	my $value = "$hours hour(s), $minutes minute(s), $seconds second(s)";
	return $value;
}

sub countdown
{
	$|++;
	for my $i (reverse 0 .. $seconds_until)
	{
		my $readable = readable($i);
		print "\r$readable remaining.";
		sleep 1;
	}
}
#sleep($seconds_until);