boxcar_push.pl

!/usr/bin/perl -w

require LWP::UserAgent;

my $ua = LWP::UserAgent->new; 
my $boxcarurl = 'https://new.boxcar.io/api/notifications'; 
# Put your Boxcar token in this file:
my $accesstoken = `cat ~/.boxcartoken`; 
chomp($accesstoken);

sub boxcarpush {
	my %notification = @_; 
	my %fields = (
	  'user_credentials' => $accesstoken, 
	); 
	
	foreach (keys %notification) { 
	  $fields{"notification[$_]"} = $notification{$_}; 
	} 
	$ua->post($boxcarurl, \%fields); 
}

boxcarpush(
	title => 'message title', 
	long_message => 'Okay, this is <b>fun</b>.', 
	sound => 'bird-1', 
); 

slight nitpick: you're missing the # at the beginning of the first line.