mu: add page (#7572)

pages/common/mu.md

@@ -0,0 +1,32 @@
+# mu
+
+> Index and search emails from a local Maildir.
+> More information: <https://man.cx/mu>.
+
+- Initialize the email database, optionally specifying the Maildir directory and email addresses:
+
+`mu init --maildir={{path/to/directory}} --my-address={{name@example.com}}`
+
+- Index new emails:
+
+`mu index`
+
+- Find messages using a specific keyword (in message body, subject, sender, ...):
+
+`mu find {{keyword}}`
+
+- Find messages to Alice with subject `jellyfish` containing the words `apples` or `oranges`:
+
+`mu find to:{{alice}} subject:{{jellyfish}} {{apples}} OR {{oranges}}`
+
+- Find unread messages about words starting with `soc` (the `*` only works at the end of the search term) in the Sent Items folder:
+
+`mu find 'subject:{{soc}}*' flag:{{unread}} maildir:'/{{Sent Items}}'`
+
+- Find messages from Sam with attached images, between 2 KiB and 2 MiB, written in 2021:
+
+`mu find 'mime:{{image/*}} size:{{2k..2m}} date:{{20210101..20211231}} from:{{sam}}`
+
+- List contacts with `Bob` in either name or email address:
+
+`mu cfind {{Bob}}`