+generally extremely fast.
+
+You can use the `post-new` hook, which is automatically run after `notmuch new`,
+to do post-processing. See `man notmuch-hooks` for details on hooks.
+
+## Tagging based on content
+
+Since notmuch currently does not index arbitrary headers, it can be
+useful to tag based on content. Here is a snippet that would fit with
+the 'new' tag approach discussed above.
+
+ for mid in $(notmuch search --output=messages tag:new); do
+ if notmuch show --format=raw "$mid" 2>/dev/null | awk '!NF{exit 1} /^X-Spam_bar: \+\+\+\+\+\+\+\+/ {exit 0}'; then
+ notmuch tag +spam "$mid"
+ fi
+ done
+
+
+## Other solutions
+
+* [Carl Worth's approach to tagging](https://notmuchmail.org/pipermail/notmuch/2010/001691.html). It
+ is email id:87r5o8stbj.fsf@yoom.home.cworth.org in the notmuch
+ mailing list archives.