Perl get SSL certificate subject alternative names (aka aliases)

#!/usr/local/bin/perl -w

use strict;

my $website = $ARGV[0] || '';

die "usage: $0 <website:sslport>\n" if (($website eq '') || ($website !~ m!^\S+:\d+$!o));

my $openssl = '/usr/local/bin/openssl';

die "openssl binary not found at $openssl\n" if ( ! -x $openssl );

my $s_client_output = qx{ echo | $openssl s_client -connect $website 2> /dev/null };

my $certcount = 0;

while ($s_client_output =~ m!(-----BEGIN CERTIFICATE-----.*?-----END CERTIFICATE-----).*?!smg) {
    my $cert_text = $1;
    my $x509_out = qx{ echo '$cert_text' | $openssl x509 -noout -text 2> /dev/null };
    while ($x509_out =~ m!DNS:([\w\-\.\*]+).*?!smg) {
        my $alias = $1;
        printf "alias for %s (%d) == %s\n", $website, $certcount, $alias;
    }
    $certcount++;
}