diff --git a/plugins/tls_cert b/plugins/tls_cert
index fede0e0..e4d52fa 100644
--- a/plugins/tls_cert
+++ b/plugins/tls_cert
@@ -1,4 +1,6 @@
-#!perl -w
+#!/usr/bin/perl
+
+use strict;
 use warnings;
 
 # Very basic script to create TLS certificates for qpsmtpd
@@ -45,6 +47,7 @@ my $CA_key = 'ssl/qpsmtpd-ca.key';
 my $CA_crt = 'ssl/qpsmtpd-ca.crt';
 my $CA_serial = 'ssl/.cert.serial';
 
+my $template;
 my ($CA, $CAfilename) = tempfile( $template, DIR => "ssl", UNLINK => 1);
 
 print ${CA} return_cfg('CA');