If you have Net::DNS lying around this is a snap to write:
#! /usr/local/bin/perl -w
use strict;
use Net::DNS;
my $dns = new Net::DNS::Resolver;
for my $domain( @ARGV ) {
my $mx = $dns->query( $domain, 'MX' );
print "$domain\n";
foreach my $rr ($mx->answer) {
print "\t", $rr->exchange, ' (', $rr->preference, ")\n";
}
}
__END__
output:
% ./mx perl.org perlmonk.org perlmonks.org perl.com
perl.org
lux.valueclick.com (20)
perlmail.valueclick.com (10)
perlmonk.org
perlmonk.org (10)
perlmonks.org
mail.egl.net (5)
perl.com
mail.perl.com (0)
print@_{sort keys %_},$/if%_=split//,'= & *a?b:e\f/h^h!j+n,o@o;r$s-t%t#u' | 