SlackBuildsOrg/network/nmh

nmh (new MH) is a powerful electronic mail handling system.  nmh
consists of a collection of fairly simple single-purpose programs
to send, receive, save, retrieve, and manipulate e-mail
messages. Since nmh is a suite rather than a single monolithic
program, you may freely intersperse nmh commands with other
commands at your shell prompt, or write custom scripts which use
these commands in flexible ways.