Notmuch is a great mail indexing tool that can also be used in conjunction with existing Mail User Agents (MUA) instead of replacing them. The advantage of such mixed solutions is that users can benefit from notmuch features (such as full-text search and thread reconstruction) without having to change MUA.
Using Notmuch with bare Mutt, the old fashioned way
notmuch-mutt, which will create a "virtual" maildir folder with search results whenever a search is made. The upside is that you can search all your folders simultanously; the downside is that your modifications in the results listing do not carry over, also having to switch folders comes with some more annoyances.
A how to use Notmuch with Mutt has been written by Stefano Zacchiroli.
(Note by the howto author: I've linked the howto from this wiki rather than splicing it in, in order to avoid duplication of information. If you think it would be better to have it here, feel free to copy the text here. The howto is available in markdown syntax from the Git repository of my homepage.)
Using a simple macro that will emulate the "limit" mutt functionality
See the alternative notmuch integration blog post for instructions and details, or simply put these two macros to your muttrc:
# 'L' performs a notmuch query, showing only the results macro index L "<enter-command>unset wait_key<enter><shell-escape>read -p 'notmuch query: ' x; echo \$x >~/.cache/mutt_terms<enter><limit>~i \"\`notmuch search --output=messages \$(cat ~/.cache/mutt_terms) | head -n 600 | perl -le '@a=<>;chomp@a;s/\^id:// for@a;$,=\"|\";print@a'\`\"<enter>" "show only messages matching a notmuch pattern" # 'a' shows all messages again (supersedes default <alias> binding) macro index a "<limit>all\n" "show all messages (undo limit)"
The upside (if you are used to working in the context of a single folder) is that this really does use the limit functionality of mutt and you are still in your original folder. The downside is that this approach has scaling problems and works well only for reasonably specific queries.
Notmuchfs provides virtual maildirs at the file system level, and mutt can be placed on top. See README.mutt