SCAN(1)
NAME
scan - produce a one line per message scan listing
SYNOPSIS
scan [+folder] [msgs] [-clear] [-noclear] [-form format-
file] [-format string] [-header] [-noheader]
[-width columns] [-reverse] [-noreverse] [-file file-
name]
[-version] [-help]
DESCRIPTION
Scan produces a one-line-per-message listing of the speci-
fied folder or messages. Each scan line contains the mes-
sage number (name), the date, the "From:" field, the "Sub-
ject" 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 modification 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 spec-
ified 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 mes-
sages.
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 encoding. You should set the MM_CHARSET envi-
ronment 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.
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 maildrop file as produced by packf.
This listing includes every message in the file (you can't
scan individual messages). The switch `-reverse' is
ignored with this option.
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 information).
If the `-clear' switch is used and scan's output is
directed to a terminal, then scan will consult the envi-
ronment 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 exit-
ing.
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 formatted listing of all mes-
sages 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 additional 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
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 feature is handy for scanning a draft folder, as mes-
sage drafts usually aren't allowed to have dates in them.
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
SEE ALSO
inc(1) pick(1) show(1) mh-format(5)
DEFAULTS
`+folder' defaults to the folder current
`msgs' defaults to all
`-format' defaulted as described above
`-noheader'
`-width' defaulted to the width of the terminal
CONTEXT
If a folder is given, it will become the current folder.
HISTORY
Prior to using the format string mechanism, `-header' used
to generate a heading saying what each column in the list-
ing was. Format strings prevent this from happening.
BUGS
The argument to the `-format' switch must be interpreted
as a single token by the shell that invokes scan. There-
fore, one must usually place the argument to this switch
inside double-quotes.
The value of each component escape is set by scan to the
contents of the first message header scan encounters with
the corresponding component name; any following headers
with the same component name are ignored.