Columbia MM
MM Manual


You can edit mail in your mail file. You can for example shorten a very long message by deleting parts you don't want to keep, or you can reformat it so it is easier to read, or you might want to change the subject line to something that means more to you.


The command edit brings a message into the editor, Emacs, so you can make changes to it. At the MM> prompt, supply a message number (edit one message at a time), or just type edit at the R> prompt.

MM>edit 73

Return-Path: <jb51>
Received: by (5.59/FCB)
        id AA01344; Monday, 7 Sep 92 10:50:29 EDT
Date: Monday, 7 Sep 92 10:50:28 EDT
From: Joe Brennan <>
To: fb2
Cc: mm33, hk12
Subject: Meeting on Sept 21
Message-Id: <>

Let's meet on Sept 21 at 2:00 to go over plans for this semester.


-----Emacs: *MM Message*           (Text)----All-----------------------------
Don't forget to save your buffers if you want your changes to take effect

You can use Emacs commands to edit any part of the message. Finish with control-x control-z, and answer Emacs's question whether to save the changes with y or yes.

As suggested above, you might want to delete portions of a long message, to save only the parts you want and conserve disk space. In Emacs, deletion can be done by marking one end of a region with control-@ (or control-_), moving the cursor to the other end, and then using control-w to wipe out. Another method is to use control-k to wipe out lines. See Emacs documentation.

Another good reason to edit would be to reformat a document that is hard to read because the lines are too long or short, particularly where the line length is wider than your terminal. In Emacs, meta-q for example will fill a paragraph to standard line length; there are other similar commands.

You can change the header fields just as easily. The usual one to change is Subject, which you might want to make into some phrase more relevant to you than the one the sender used.

You can correct or check spelling using the spell command without going into Emacs.


As you may realize, it would be possible to change a message, and then show it to someone, or even forward it by mail to someone, and claim that it is the original wording of a message. While you may be ethical enough not to do so, bear in mind that it can be done. There are various ways to alter or forge electronic mail. Do not assume that all messages must be authentic. Particularly, if you see something that surprises you or otherwise seems wrong, check with the supposed sender.


Do not edit mbox (or other mail files) directly from the UNIX shell. In other words, do not start Emacs at the shell and visit mbox. The problem is that mbox is a specially formatted file, and if you accidentally change one of the control lines in the file, or add a line in a bad place, MM may be unable to read the file.

Please let MM maintain the mail files. Use edit to change messages, and use delete and expunge to remove messages.

If you are curious to see what the file looks like, use a read-only command like cat or more, rather than an editor.

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