[[!img notmuch-logo.png alt="Notmuch logo" class="left"]] # Searching with notmuch What good is an advanced indexing mail client if we don't know how to use it to actually find e-mail? Please see the [[notmuch-search-terms manual page|manpages/notmuch-search-terms-7]] first for an overview of the search syntax, including the prefixes (such as "to:") and date range searches. Notmuch uses the [Xapian](http://xapian.org/) search engine. The [Xapian QueryParser](http://xapian.org/docs/queryparser.html) documentation has a generic description of the search language. The intended audience is developers wanting to use Xapian in their applications; this page attempts to explain it to users of Notmuch. ## Stemming See the [Wikipedia article](http://en.wikipedia.org/wiki/Stemming) for the detailed description. What this means for us is that these searches notmuch search detailed notmuch search details notmuch search detail will all return identical results, because Xapian first "reduces" the term to the common stem (here 'detail') and then performs the search. The only way to turn this off is the so called search for proper names: a search for a capitalized word will be performed unstemmed, so that one can search for "John" and not get results for "Johnson". ### Languages other than English Stemming is currently only supported for English. Words in other languages will be performed unstemmed unless somebody teaches Xapian how to perform stemming for that language. ## Synonyms (how is the QueryParser configured?) ## Wildcards It is possible to use a trailing '\*' as a wildcard. A search for 'wildc\*' will match 'wildcard', 'wildcat', etc. ## Operators Xapian implements the usual operators and a few more that are useful when searching e-mails. *Note: The operators need not be capitalized for notmuch, so 'NOT' and 'not' are equivalent. The capitalized form is used below only for readability* ### '+' and '-' notmuch search +term1 will only return results that contain 'term1'. notmuch search -term2 will return results that do not contain 'term2'. '+' and '-' can also be used on bracketed expressions or phrases (see below). ### AND and NOT notmuch search term1 AND term2 will return results that contain **both** 'term1' and 'term2'. If no explicit operator is provided all search terms are connected by an implicit AND, so these two searches: notmuch search term1 AND term2 notmuch search term1 term2 are equivalent. notmuch search term1 NOT term2 will return results that contain 'term1' but do not contain 'term2'. For a query that looks more like natural language you can also use AND NOT notmuch search term1 AND NOT term2 ### XOR (exclusive OR) notmuch search term1 XOR term2 will return results that contain either 'term1' or 'term2', but **not** both. ### OR notmuch search term1 OR term2 will return results that contain either 'term1' or 'term2'. ### Brackets Operators above are listed in the default order of precedence. One can override the precedence using bracketed expressions: notmuch search term1 AND term2 OR term3 is the same as notmuch search (term1 AND term2) OR term3 but not the same as notmuch search term1 AND (term2 OR term3) ### NEAR notmuch search term1 NEAR term2 will return results where term1 is within 10 words of term2. The threshold can be set like this: notmuch search term1 NEAR/2 term2 ### ADJ (adjacent) notmuch search term1 ADJ term2 will return results where term1 is within 10 words of term2, but in the same order as in the query. The threshold can be set the same as with NEAR: notmuch search term1 ADJ/7 term2 ### Phrases According to the Xapian documentation a phrase surrounded with double quotes (like this: "my phrase") will return results that match everything containing "that exact phrase", but hyphenated words or e-mail addresses are also treated as phrases. In practice this means that these two searches are **not** equivalent: notmuch search "Debian Project" notmuch search Debian ADJ/1 Project ## Prefix searches You can search your collection by using several prefixes, like this: notmuch search from:john This will return results where 'john' appears in the name or the e-mail address. See 'notmuch help search-terms' for a complete list of prefixes. ### Message IDs An important concept for notmuch is the Message-Id, which is a unique identifier for each message. Individual messages can be accessed via their message ID with the "id:" prefix: notmuch search id: ## Range searches Since notmuch is about (large) e-mail collections it is very useful to be able to search for e-mails within a specific date range. This will work: notmuch search date:.. For `` and ``, notmuch understands a variety of standard and natural ways of expressing dates and times, both in absolute terms ("2012-10-24") and in relative terms ("yesterday"). Please refer to the [[notmuch-search-terms manual page|manpages/notmuch-search-terms-7]] for details.