X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=faq.mdwn;h=bb0efaa90c2b458ca5e6ec9ea1486e52d7da072a;hb=6af7f7dbf56bba07b8e3dcd567f51230c230b8d4;hp=52fccf31031a38254170ecaa91d0058185afcf53;hpb=16e642531190fdaf2f62077f97d39c275e4afd01;p=notmuch-wiki

diff --git a/faq.mdwn b/faq.mdwn
index 52fccf3..bb0efaa 100644
--- a/faq.mdwn
+++ b/faq.mdwn
@@ -22,7 +22,34 @@ See [[excluding]].
 
 ## How do I configure the citation line when replying in Emacs?
 
-   (setq message-citation-line-format "On %a, %d %b %Y, %f wrote:")
-   (setq message-citation-line-function 'message-insert-formatted-citation-line)
+        (setq message-citation-line-format "On %a, %d %b %Y, %f wrote:")
+        (setq message-citation-line-function 'message-insert-formatted-citation-line)
 
 See help for `message-citation-line-format` for details.
+
+## How do I search for messages that have no tags?
+
+Unfortunately, there is no way to do this directly.
+
+However, it's possible to accomplish this using two searches in shell. First,
+you need to query all tags in the database, and transform the result into a
+query that matches messages that have none of those tags:
+
+        $ notmuch search --output=tags \* | sed 's/^/not tag:/;2~1s/^/and /'
+
+Next, use that to query the messages:
+
+        $ notmuch search $(notmuch search --output=tags \* | \
+                sed 's/^/not tag:/;2~1s/^/and /')
+
+## How do I search for punctuation, specific special characters, or regexp?
+
+Please see the [[notmuch-search-terms manual
+page|manpages/notmuch-search-terms-7]] first.
+
+The main thing to understand is that Xapian, and therefore Notmuch, searches are
+closer to natural language searches than regular expression
+searches. Punctuation is mostly ignored.
+
+The boolean prefix searches (see Boolean and Probabilistic Prefixes in the man
+page), such as tag: or path: searches, need an exact match.