Cleancode email
Cleancode eMail is a simple command line Unix utility to send SMTP email, written to be as portable as possible. It is known to compile and work under Linux, BSD, Solaris, OS X, Cygwin and a few other Unix/Linux-like operating systems.
Features
Cleancode eMail offers very standard features for sending mail via SMTP such as SMTP AUTH (LOGIN and PLAIN only), simple attachments (base64 encoding), header editing, address book and signatures. It is easy to use and learn and can be used in scripts very easily. The lack of modern features helps Cleancode eMail stand out as a fast, efficient and helpful tool for system administrators in Unix-like environments, as that was its intentional purpose when first developed.
History
Cleancode eMail started in September 2001 and is currently still maintained and developed by the original author, Dean Jones.