femail

Femail is a sendmail-compatible command line interface that can forward mail via SMTP. What sets Femail apart from other implementations is its adherence to RFC 2821 and 2822 standards. Additionally, Femail embeds extra environment information from Apache in the header (if present) to help track down abuse.

As for the options available, users can choose to only use IPv4 or IPv6 with the "-4" and "-6" flags, respectively. The sender's name can be set with the "-F" flag followed by the desired name. Similarly, the sender's address can be set with the "-f" flag followed by the desired address. By default, Femail tries to parse the sender from the message and uses "login@hostname" if that information is not present.

The "-t" flag allows users to read recipients from the message given on stdin in addition to the recipients given on the command line. Finally, verbose operation can be enabled with the "-v" flag.

All in all, Femail is a reliable and versatile option for sending mail via SMTP. With its adherence to RFC standards and various customization options, it is a solid choice for those in need of a sendmail-compatible command line interface.