man > scan(1)

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SCAN(1mh) SCAN(1mh)

NAME
scan - produce a summary listing of nmh messages

SYNOPSIS

scan [-help] [-version] [+folder] [msgs] [-clear | -noclear] [-form formatfile] [-format
string] [-header | -noheader] [-width columns] [-reverse | -noreverse] [-file filename]

DESCRIPTION
scan produces a one-line-per-message listing of the specified folder or messages. Each scan
line contains the message number (name), the date, the “From:” field, the “Subject” field,
and, if room allows, some of the body of the message. For example:

15+ 10/05 crocker nned <<Last week I asked some of
16- 10/05 crocker message id format <<I recommend
18 10/06 brien Re: Exit status from mkdir
19 10/07*brien “scan” listing format in nmh

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 -annotate switch to the repl command).

The `*' on message 19 indicates that no “Date:” header was present. The time of last modifi‐
cation of the message is given instead.

If there is sufficient room left on the scan line after the subject, the line will be filled
with text from the body, preceded by “<<”, and terminated by “>>” if the body is sufficiently
short. scan actually reads each of the specified messages and parses them to extract the de‐
sired fields. During parsing, appropriate error messages will be produced if there are for‐
mat errors in any of the messages.

By default, scan will decode RFC 2047 (MIME) encoding in these scan listings. scan will only
decode these fields if your terminal can natively display the character set used in the en‐
coding. You should set the appropriate locale(1) environment variables to your native char‐
acter set, if it is not US-ASCII. See locale(1) for more details on the appropriate environ‐
ment variables.

The switch -reverse, makes scan list the messages in reverse order.

The -file filename switch allows the user to obtain a scan listing of a mail drop. This
listing includes every message in the mail drop (you can't scan individual messages). The
switch -reverse is ignored with this option. If filename is a file, it can be in mbox or
MMDF format, as produced by packf. If filename is a directory, it is considered to be in
Maildir format.

The switch -width columns may be used to specify the width of the scan line. The default is
to use the width of the terminal.

The -header switch produces a header line prior to the scan listing. Currently, the name of
the folder and the current date and time are output (see the HISTORY section for more infor‐
mation).

If the -clear switch is used and scan's output is directed to a terminal, then scan will con‐
sult the environment variables $TERM and $TERMCAP to determine your terminal type in order to
find out how to clear the screen prior to exiting. If the -clear switch is used and scan's
output is not directed to a terminal (e.g., a pipe or a file), then scan will send a formfeed
prior to exiting.

For example, the command:

(scan -clear -header; show all -show pr -f) | lpr

produces a scan listing of the current folder, followed by a formfeed, followed by a format‐
ted listing of all messages in the folder, one per page. Omitting “-show pr -f” will cause
the messages to be concatenated, separated by a one-line header and two blank lines.

To override the output format used by scan, the -format string or -form file switches are
used. This permits individual fields of the scan listing to be extracted with ease. The
string is simply a format string and the file is simply a format file. See mh-format(5) for
the details.

In addition to the standard mh-format(5) escapes, scan also recognizes the following addi‐
tional component escapes:

Escape Returns Description
body string the (compressed) first part of the body
dtimenow date the current date
folder string the name of the current folder

{body} returns a string without MIME decoding, i.e. the MIME boundary separator may be the
first text shown.

If no date header is present in the message, the function escapes which operate on {date}
will return values for the date of last modification of the message file itself. This fea‐
ture is handy for scanning a draft folder, as message drafts usually aren't allowed to have
dates in them.

The /etc/nmh directory contains several format files as examples of customized scan output.

scan will update the nmh context prior to starting the listing, so interrupting a long scan
listing preserves the new context. nmh purists hate this idea.

FILES
$HOME/.mh_profile The user profile

PROFILE COMPONENTS
Path: To determine the user's nmh directory
Alternate-Mailboxes: To determine the user's mailboxes
Current-Folder: To find the default current folder