mh6.tex

早期freebsd实现

give these \MH/ commands precise instructions on how to format their output.

As a result,
the \pgm{inc} and \pgm{scan} programs no longer have the
\switch{size}, \switch{nosize},
\switch{time}, \switch{notime},
\switch{numdate}, and \switch{nonumdate}
switches.
These switches have been replaced with the
\switch{form~formatfile} switch and the \switch{format~string} switch.
The former directs the program to consult the named file for the format
strings.
The latter directs the program to use the named string as the format.
To get the behavior of the old \switch{time} option,
use the \switch{form~scan.time} option.
Similarly,
to get the effect of \switch{size},
use \switch{form~scan.size}.

The \pgm{repl} command uses a file containing format files to
indicate how the reply draft should be constructed.
Note that reply templates prior to \mh6 are incompatible with \mh5.
Don't worry though,
it's quite easy to convert the templates by hand.
(Those clever enough to have written a reply template to begin with won't
have {\em any\/} problem.)

Similarly, when the \pgm{forw} program is constructing a digest,
it uses a file containing format strings to indicate how to build the
encapsulating draft.

\section*	{News}
The depreciated \MH/ news system (from \mh1) is now de-supported.
Use the ``hoopy'' BBoards facility instead.

\section*	{BBoards}
\MH/ maintainers take note:
the default home directory for the bboards login has changed from
\file{/usr/bboards/} to \file{/usr/spool/bboards/}.
Use the \eg{bbhome} directive in your \MH/ configuration file to set
it back to the old value if you wish.

In addition, the aliases field for a BBoard in the BBoards file is now
deemed useful only for addressing, not for user input to \pgm{bbc}.
This means when giving the name of a BBoard to \pgm{bbc},
only the official name should be used.

A final note for mailsystem maintainers:
the \MMDFII/ BBoards channel and the \SendMail/ BBoards mailer have been
modified to use the standard message encapsulation format when returning
failed messages to the list maintainer.
This means that the failure notices that the maintainer receives can
simply be \pgm{burst}.

\subsection*	{New Switches in bbc}
The \pgm{bbc} program permits you to specify the \eg{mshproc} to use on the
command line by using the \switch{mshproc~program} option.
In addition, options which aren't understood by \pgm{bbc} are passed along to
the \eg{mshproc}.

In addition, the following commands
pass any unrecognized switches on to the program that they invoke:
\pgm{bbc}, \pgm{next}, \pgm{show}, \pgm{prev}, and \pgm{vmh}.

\subsection*	{Distributed BBoards}
If both BBoards and POP (see the next section) are enabled,
then distributed BBoards can be supported on top of the POP service.
This allows the \MH/ user to read BBoards on a server machine
instead of the local host
(which saves a lot of wasted disk space when the same BBoards are replicated
several times at a site with several hosts).
See the {\em Administrator's Guide\/} for information on how this can be made
completely transparent to the \MH/ user.

If you have several machines at your site running 4.2\bsd/~\unix/
and connected by an \ethernet/ (or other high-speed LAN),
you {\em want\/} this software.

\subsection*	{Visual Front-End to msh}
A simple window management protocol has been implemented for \MH/ programs
that might wish to act as a back-end to a sophisticated visual front-end.

The first implementation of a server side (front-end) program is \pgm{vmh},
which uses \man curses(3) to maintain a split-screen interface.
Perhaps look for a \pgm{mhtool} program for the SUN next!

The \pgm{msh} program has been modified to speak the client side (back-end)
of this protocol, if so directed.
At present, \pgm{msh} is the only program in the \MH/ distribution which
implements the client side of the window management protocol.

\subsection*	{Updates in msh}
Prior to quitting,
the \pgm{msh} command now asks if the \pgm{packf\/}'d file you've been
perusing should be updated if you've modified it and the file is writable by
you.
The file can be modified by using \pgm{burst}, \pgm{rmm}, \pgm{rmm},
or \pgm{sortm} commands.
The file can also be modified by using the \pgm{refile} command without the
\switch{link} option.
(Or course,
the \switch{link} option doesn't actually link anything to the file.)

\section*	{Distributed Mail}
\MH/ now contains a powerful facility for doing distributed mail
(having \MH/ reside on a host different than the message transport agent).
For general information,
consult either the 
{\em MH.5: How to process 200 messages a day and still get some real work
done} paper,
or the {\em MH: A Multifarious User Agent} paper.
For specific information,
consult the {\em Administrator's Guide}.
Here's a brief synopsis:

This POP facility in \MH/ is based on a modification of the ARPA Post
Office Protocol (POP).
A POP {\em subscriber\/} is a remote user,
on a POP {\em client host},
that wishes to pick-up mail on a POP {\em service host}.

There are two ways to administer POP:
\begin{itemize}
\item	Naive Mode\hbreak
Each user-id in the \man passwd(5) file is considered a POP subscriber.
No changes are required for the mailsystem on the POP service host.
However,
this method requires that each POP subscriber have an entry in the password
file.
The POP server will fetch the user's mail from wherever maildrops are kept on
the POP service host.
This means that if maildrops are kept in the user's home directory,
then each POP subscriber must have a home directory.

\item	Smart Mode\hbreak
This is based on the notion that the list of POP subscribers and the list of
login users are completely separate name spaces.
A separate database (similar to the \man BBoards(5) file)
is used to record information about each POP subscriber.
Unfortunately,
the local mailsystem must be changed to reflect this.
This requires two changes (both of which are simple):
\begin{enumerate}
\item	Aliasing\hbreak
	The aliasing mechanism is augmented so that POP subscriber addresses
	are diverted to a special delivery mechanism.
	\MH/ comes with a program, \man popaka(8), which generates the
	additional information to be put in the mailsystem's alias file.
\item	Delivery\hbreak
	A special POP channel (for \MMDFII/) or POP mailer (for \SendMail/)
	performs the actual delivery (\mh6 supplies both).
	All it really does is just place the mail in the POP spool area.
\end{enumerate}
Clever mailsystem people will note that
the POP mechanism is really a special case of the more general
BBoards mechanism.
\end{itemize}
These two different philosophies are not compatible on the same POP service
host: one or the other, but not both, may be run.

In addition, there is one user-visible difference,
which the administrator controls the availability of.
The difference is whether the POP subscriber must supply a password to the POP
server:
\begin{itemize}
\item	ARPA standard method\hbreak
This uses the standard ARPA technique of sending a username and a password.
The appropriate programs (\pgm{inc}, \pgm{msgchk}, and possibly \pgm{bbc\/})
will prompt the user for this information.

\item	\unix/ remote method\hbreak
This uses the Berkeley \unix/ reserved port method for authentication.
This requires that the two or three mentioned above programs be {\em setuid\/}
to root.
(There are no known holes in any of these programs.)
\end{itemize}
These two different philosophies are compatible on the same POP service host:
to selectively disable RPOP for hosts which aren't trusted,
either modify the \file{.rhosts} file in the case of POP subscribers being
\unix/ logins,
or zero the contents of network address field of the \man pop(5) file for the
desired POP subscribers.

The \pgm{inc} command also has two other switches when \MH/ is enabled for
POP:
\switch{pack~file} and \switch{nopack}.
Normally,
\pgm{inc} will use the POP to incorporate mail from a POP service host into
an \MH/ folder (\eg{+inbox}).
However,
there are some misguided individuals who prefer to \pgm{msh} to read their
maildrop.
By using the \switch{pack~file} option,
these individuals can direct \pgm{inc} to fetch their maildrop from the POP
service host and store it locally in the named file.
As expected, \pgm{inc} will treat the local file as a maildrop,
performing the appropriate locking protocols.

\section*	{Rcvmail hooks}
In order to offer users of \MH/ increated rcvmail hook functionality,
the \pgm{slocal} program has been upgraded to support the semantics of
the \MMDFII/ mail-delivery mechanism.
This means that users of \mh6 can maintain identical \file{.maildelivery}
files regardless of the underlying transport system.
See \man mhook(1) for all the details.

\subsection*	{Field change in rcvpack}
The \pgm{rcvpack} rcvmail hook now adds the field name \eg{Delivery-Date:}
instead of \eg{Cron-Date:} to messages it \pgm{pack\/}s.

\section*	{Other Changes}
Here's the miscellany:

\subsection*	{Continuation Lines}
Alias files used by \MH/,
display templates used by \pgm{mhl},
and format files used by \pgm{forw}, \pgm{repl}, and \pgm{scan} all support
a standard continuation line syntax.
To continue a line in one of these files,
simply end the line with the backslash character (`$\backslash$').
All the other files used by \MH/ are in 822--format,
so the 822--continuation mechanism is used.%
\nfootnote{Looking back,
it would have been best had all files in \MH/ used the 822--format.}

\subsection*	{Modifications to show}
The \switch{format}, \switch{noformat}, \switch{pr}, and \switch{nopr}
options to \pgm{show} have gone away in favor of a more general mechanism.
The \switch{showproc~program} option tells \pgm{show}
(or \pgm{next} or \pgm{prev\/}) to use the named program as the \eg{showproc}.
The \switch{noshowproc} option tells \pgm{show}, et. al.,
to use the \man cat(1) program instead of a \eg{showproc}.
As a result, the profile entry \eg{prproc} is no longer used.

\subsection*	{Front-End to mhl}
When outputting to a terminal,
the \pgm{mhl} program now runs the program denoted by the profile entry
\eg{moreproc}.
If this entry is not present,
the default is the UCB \pgm{more} program.
If the entry is non-empty,
then that program is spliced between \pgm{mhl} and the user's terminal.
The author uses the \pgm{less} program as his \eg{moreproc}.

Of course,
if \pgm{mhl} isn't outputting to a terminal,
then \eg{moreproc} is not invoked.

\subsection*	{Switch change in inc}
The \switch{ms~ms-file} switch in \pgm{inc} has been changed to
\switch{file~name} to be more consistent.

\subsection*	{Complex Expressions in pick}
The \pgm{pick} command now handles complex boolean expressions.

\subsection*	{Defaults change in prompter and burst}
The \switch{prepend} option is now the default in \pgm{prompter}.
The \switch{noinplace} option is now the default in \pgm{burst}.

\subsection*	{Interactive option in rmf}
The \pgm{rmf} program has been changed to support an \switch{interactive}
switch.
If given,
then the user is prompted regarding whether the folder should be deleted.
If the folder to be removed is not given by the user,
this switch is defaulted to on.

\subsection*	{Trusted Mail Interface}
\MH/ now has an interface for so-called ``trusted mail'' applications.
Although the modifications to \MH/ to support this are in the public domain,
the actual library that \MH/ uses is not.
Contact Professor David J.~Farber ({\sf Farber@UDel\/}) for more information.

\bibliography{mh6}

\showsummary

\end{document}