Emacs Gnus: Searching Mail

There are several ways to find messages in Emacs. From the summary buffer, you can use / o (gnus-summary-insert-old-articles) to display all or some old messages. You can then scan through the headers in the summary buffer by using C-s (isearch-forward), or you can limit the displayed messages with these commands:

Messages from a given author/ agnus-summary-limit-to-author
Messages whose subjects matching a given regular expression/ /gnus-summary-limit-to-subject
Messages that match a given extra header/ xgnus-summary-limit-to-extra-headers
Messages at least N days old/ tgnus-summary-limit-to-age

Limits work on the messages that are currently displayed, so you can apply multiple limits. If you make a mistake, use / w (gnus-summary-pop-limit) to remove the previous limit. You can repeat / w (gnus-summary-pop-limit) until satisfied. To remove all the limits, type C-u / w (gnus-summary-popl-limit).

If you specify a prefix, the limit's meaning is reversed. For example, C-u / a (gnus-summary-limit-to-author) will remove the messages from the matching author or authors.

You can use Gnus to search the currently-displayed messages by using M-s (gnus-summary-search-article-forward) and M-r (gnus-summary-search-article-backward).

If you want to search a lot of mail, you'll find NNIR handy. NNIR is a front-end to mail search engines which can index your mail and return search results quickly. If you want to use NNIR with a local or remote IMAP server, you will need to use nnir.el and imap.el. If you download your mail using fetchmail or connect to a POP3 server and use an nnml backend, you can use NNIR with a search engine such as swish-e to search your ~/Mail directory efficiently.

1.6.7.1 Setting up IMAP and NNIR

If you use IMAP, then your mail is stored on the mail server and you'll need to use the IMAP search interface to search through it. Download nnir.el from http://www.emacswiki.org/cgi-bin/wiki/download/nnir.el and save it to your ~/elisp directory. You will also need an imap.el that is newer than the one that comes with Emacs 22. Download imap.el from http://www.emacswiki.org/cgi-bin/wiki/download/imap.el and save it to your ~/elisp directory as well. Because Gnus comes with an older version of imap.el, you will need to make sure that the new version of imap.el is loaded. Add the following to your ~/.gnus:

(add-to-list 'load-path "~/elisp")
(load-file "~/elisp/imap.el")
(require 'nnir)

Restart your Emacs. You can check if the correct version of imap.el has been loaded by typing M-x locate-library and specifying imap.el. If Emacs reports "~/elisp/imap.el", then Gnus is configured to use the updated imap.el.

1.6.7.2 Setting up POP3 and NNIR

If you use the configuration for POP3 that is suggested in this chapter, then your mail is stored in the nnml backend, which uses one file per message. To search this using NNIR, to install nnir.el and an external search mail engine. The Namazu search engine runs on Linux, UNIX, and Microsoft Windows, so that's what we'll talk about here. To find and configure other mail search engines supported by NNIR, check out the comments in nnir.el.

First, you'll need to download and install Namazu. If Namazu is available as a package for your distribution, install it that way, as it depends on a number of other programs. An installer for Microsoft Windows can be found at http://www.namazu.org/windows/ . If you need to build Namazu from source, you can get the source code and instructions from http://www.namazu.org .

After you've installed Namazu, create a directory for Namazu's index files, such as ~/.namazu-mail. Then index your mail by typing this at the command-line:

mknmz --mailnews -O ~/.namazu-mail ~/Mail

and add the following to your ~/.gnus:

(add-to-list 'load-path "~/elisp")
(require 'nnir)
(setq nnir-search-engine 'namazu)
(setq nnir-namazu-index-directory (expand-file-name "~/.namazu-mail"))
(setq nnir-namazu-remove-prefix (expand-file-name "~/Mail"))
(setq nnir-mail-backend gnus-select-method)
1.6.7.3 Searching your mail with NNIR

From the group buffer displayed by M-x gnus, you can type G G (gnus-group-make-nnir-group) to search your mail for a keyword.

If you're using the Namazu search engine, then you can use more sophisticated search queries such as:

Linux Emacsmessages that contain both "Linux" and "Emacs"
Linux or Emacsmessages that contain either "Linux" or "Emacs"
Emacs not Linuxmessages that contain "Emacs" but not "Linux"
Emacs and (Linux or Windows)messages that contain "Emacs" and either "Linux" or "Windows"
"apple pie"messages that contain the phrase "apple pie"
{apple pie}messages that contain the phrase "apple pie"
+from:[email protected]messages with [email protected] in the From: header
+subject:"apple pie"messages with the phrase "apple pie" in the Subject: header
+subject:apple +subject:piemessages whose Subject: headers contain both "apple" and "pie"

If matching messages are found, then you will see a temporary group with the results. Although you can't delete messages from this view, reading and replying to these messages is the same as reading and replying to regular messages.

To see a message in its original context, type G T (gnus-summary-nnir-goto-thread) from the summary buffer. This opens the message's original group. If Gnus asks you how many articles to load, press RET to accept the default of all the articles.


This is a draft for the Wicked Cool Emacs book I'm working on. =) Hope it helps!

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