RedHat does not install mailx by default

So, you use mail, or whatever RedHat installs by default. I would only use Mail::Mailer for portability reasons, but that wasn't a reason that was mentioned.

And don't forget, system() calls aren't exactly free either.

Your point being? Have you ever looked into the works of Mail::Mailer? For Unix like systems, the _default_ is to use an external mail program like mail or mailx. And guess how that's invoked? By doing a fork & exec, just like you would be doing with:

    open my $fh => "| mailx args" or die;
[download]

which my preferred way of calling mailx.

If you need to send mail, you better be using SMTP. Sure, you can use 'mail', but how can you tell if the system actually checks the mail queue. Is the mail daemon even running? Can you even assume it's going to be Sendmail? If you have your own little kingdom where certain things can be taken for granted, you can code accordingly. In general terms, though, such assumptions are risky.

Mail::Mailer isn't going to use smtp by default on a Unix system either. If it finds an executable mail or mailx, it will use that, regardless whether there's a mail daemon running or not.

As for using SMTP, I think you don't realize what you are saying. That also means you have to queue, do DNS lookups, and retry (typical up to 5 days) if there's a non-permanent failure in the delivery. Most scripts want to be finished long before email gets delivered.

Abigail