+.RS 4
+.TP 4
+.BR \-\-exclude=(true|false|all|flag)
+
+A message is called "excluded" if it matches at least one tag in
+search.tag_exclude that does not appear explicitly in the search terms.
+This option specifies whether to omit excluded messages in the search
+process.
+
+The default value,
+.BR true ,
+prevents excluded messages from matching the search terms.
+
+.B all
+additionally prevents excluded messages from appearing in displayed
+results, in effect behaving as though the excluded messages do not exist.
+
+.B false
+allows excluded messages to match search terms and appear in displayed
+results. Excluded messages are still marked in the relevant outputs.
+
+.B flag
+only has an effect when
+.BR --output=summary .
+The output is almost identical to
+.BR false ,
+but the "match count" is the number of matching non-excluded messages in the
+thread, rather than the number of matching messages.
+.RE
+
+.RS 4
+.TP 4
+.BR \-\-duplicate=N
+
+Effective with
+.BR --output=files ,
+output the Nth filename associated with each message matching the
+query (N is 1-based). If N is greater than the number of files
+associated with the message, don't print anything.
+
+Note that this option is orthogonal with the
+.BR folder:
+search prefix. The prefix matches messages based on filenames. This
+option filters filenames of the matching messages.
+.RE
+
+.SH EXIT STATUS
+
+This command supports the following special exit status codes
+
+.TP
+.B 20
+The requested format version is too old.
+.TP
+.B 21
+The requested format version is too new.
+