Pine: for email and Internet news
Pine is a well-known *nix email program which also does Usenet. It is a command-line full-screen application, and runs well in an xterm, too. It's been around since before 1992. Available as both source and binary (for various platforms, including Microsoft Windows), Pine is a well-supported application with a large user base, FAQs, and mailing lists.
Users can have files and folders, of course, including 'incoming folders'. Automatic saving of `seen’ ('read') messages is available. It has a primitive filtering capability, which can sort incoming mail into the incoming folders. One can, and is advised to, use procmail for this purpose.
Folders support message sorting and selection based on various criteria. This is useful for searching through archived messages. Sub-folders and folders on other servers are supported.
Pine includes good support for IMAP and local mail spool. It can access a couple of different mailbox formats. Lightweight Directory Access Protocol is supported through OpenLDAP.
In these days of HTML email, Pine renders HTML, but never posts HTML. In general, it appears to be very compliant with various RFCs. It even supports the new List-* headers by providing a list management interface.
An ability to define 'Roles' is useful for users who need to write email in different capacities. A role is a set of From: address, realname, and signature, which can be changed depending on a particular message. Thus a user can have different roles depending on the context of the
There is an excellent address book feature. This allows one to email address book entries to someone else so that they can be imported straight into Pine. The addressbook file itself is almost plain text and quite readable by humans.
An addressbook entry consists of a person's full name, short name (that can be typed into the from, cc, and bcc fields, and is expanded into the full email address), one or more email addresses, and a File carbon copy entry. This is where all email sent to that address ends up.
The default is the default sent-mail folder. A useful comment field is included.
Setup options are overwhelming, but help is available and considerable customization is possible. Pine's help is provided within the program, and can be accessed by pressing ^G or ? at almost any point. It is context-sensitive and hyperlinked.
Custom header definition is a useful feature for those that would have their own additional headers on their messages. You can specify any extra headers, including X-headers. Even the From:address can be changed, but that is configuration-dependant.