Mailx – an intelligent mail processing system, which has a command syntax reminiscent of ed with lines replaced by messages. It’s a free implementation of the System V mailx command and features an interface like that by default.
It is based on Berkeley Mail 8.1, is intended to provide the functionality of the POSIX mailx command, and offers extensions for MIME, IMAP, POP3, SMTP, and S/MIME. Mailx provides enhanced features for interactive use, such as caching and disconnected operation for IMAP, message threading, scoring, and filtering. It is also usable as a mail batch language, both for sending and receiving mail.
Some features are:
– Supports the MIME specifications
– Supports IMAP. In combination with either OpenSSL or Mozilla NSS, IMAPS can also be used.
– Supports caching and disconnected operation of IMAP folders.
– Supports POP3 to read messages on a remote server. In combination with OpenSSL or NSS, POP3S can also be used.
– Supports SMTP to send messages directly to a remote server.
– Supports S/MIME for signed and encrypted email (in combination with OpenSSL or NSS).
– In combination with NSS, certificates for S/MIME and SSL/TLS can be shared with Mozilla applications, and can be managed using them.
– Can display message threads and supports operations on them.
– Provides a Bayesian junk mail filter.
– Features a lot of detail improvements over previous implementations of Mail/mailx, such as IMAP-style search methods and flags for any types of folders, killing and scoring of messages, maildir folder support, an option to set the From: address directly, and the generation of References: header fields to avoid annoyances on mailing lists.
– Can be used as a mail batch language in nearly the same way as it is used interactively.