+.B Scan
+and
+.B pick
+produces a one\-line\-per\-message listing of the specified and selected
+folder or messages.
+The default format is for
+.B pick
+is to print the message number for each message.
+The default
+.B Scan
+line contains the message number
+(name), the date, the `From:' field and the `Subject' field.
+The following example shows the default output of
+.B scan
+.PP
+.RS 5
+.nf
+.ta \w'15+- 'u +\w'07/\|05x 'u +\w'Dcrocker 'u
+15+ 10/\|05 crocker nned
+16\- 10/\|05 crocker message id format
+18 10/\|06 brien Re: Exit status from mkdir
+19 10/\|07*brien `scan' listing format in mmh
+.fi
+.RE
+.PP
+The `+' on message 15 indicates that it is the current message.
+The `\-' on message 16 indicates that it has been replied to, as indicated
+by a `Replied:' component (produced by the
+.B \-annotate
+switch
+to the
+.B repl
+command).
+The `*' on message 19 indicates that no `Date:' header was
+present. The time of last modification of the message is given instead.
+.B Scan
+actually reads each of the specified messages and parses them to extract
+the desired fields. During parsing, appropriate error messages will be
+produced if there are format errors in any of the messages.
+.PP
+By default,
+.B scan
+will decode RFC-2047 (MIME) encoding in
+these scan listings.
+.B Scan
+will only decode these fields if your
+terminal can natively display the character set used in the encoding.
+You should set the MM_CHARSET environment variable to your native
+character set, if it is not US-ASCII. See the mh-profile(5) man
+page for details about this environment variable.
+.PP
+The
+.B \-file
+.I filename
+switch allows the user to obtain a
+.B scan
+listing of a maildrop file as produced by
+.BR packf .
+This listing
+includes every message in the file (you can't scan individual messages).
+.PP
+The switch
+.B \-width
+.I columns
+may be used to specify the width of
+the scan line. The default is to use the width of the terminal.
+.PP
+The command:
+.PP
+.RS 5
+(scan | pr ; show a \-showproc pr) | lpr
+.RE
+.PP
+produces a scan listing of the current folder,
+followed by a formatted listing of all messages in the folder, one
+per page. Omitting
+.RB ` "\-showproc\ pr" '
+will cause the messages to be
+concatenated, separated by a one\-line header and two blank lines.
+.PP
+To override the output format used by
+.BR scan ,
+the
+.B \-form
+.I file
+switch is used. This permits individual fields of
+the scan listing to be extracted with ease.
+.I file
+is either the name of a format file or a format string directly,
+if prepended with an equal sign `='.
+See
+.BR mh\-format (5)
+for the details.
+.PP
+In addition to the standard
+.BR mh\-format (5)
+escapes,
+.B scan
+also recognizes the following additional
+.I component
+escapes:
+.PP
+.RS 5
+.nf
+.ta \w'Dtimenow 'u +\w'Returns 'u
+.I "Escape Returns Description
+dtimenow date the current date
+folder string the name of the current folder
+.fi
+.RE
+.PP
+If no date header is present in the message, the
+.I function
+escapes
+which operate on
+.RB { date }
+will return values for the date of last
+modification of the message file itself. This feature is handy for
+scanning a draft folder, as message drafts usually aren't allowed
+to have dates in them.
+.PP
+.B scan
+will update the
+.B mmh
+context prior to starting the listing,
+so interrupting a long
+.B scan
+listing preserves the new context.
+.B nmh
+purists hate this idea.
+