SCAN(1)SCAN(1)NAMEscan - produce a one line per message scan listing
SYNOPSISscan [+folder] [msgs] [-clear | -noclear] [-form formatfile] [-format
string] [-header | -noheader] [-width columns] [-reverse | -nore‐
verse] [-file filename] [-version] [-help]
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 indi‐
cated 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 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.
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 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.
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 mes‐
sage 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 termi‐
nal, then scan will consult the environment variables $TERM and $TERM‐
CAP 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 formatted listing of all messages in the folder, one per
page. Omitting “-show pr -f” will cause the messages to be concate‐
nated, 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 message 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 ALSOpick(1), show(1), mh-format(5)DEFAULTS
`+folder' defaults to the current folder
`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 listing 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. Therefore, one must usually
place the argument to this switch inside quotes.
The value of each component escape is set by scan to the contents of
the first message header scan encounters with the corresponding compo‐
nent name; any following headers with the same component name are
ignored.
nmh-1.5-2 March 6, 2012 SCAN(1)
