mail2.nr

早期freebsd实现

command can be abbreviated to simply
.b d .
.pp
Many features of
.i Mail
can be tailored to your liking with the
.b set
command.  The
.b set
command has two forms, depending on whether you are setting
a
.i binary
option or a
.i valued
option.
Binary options are either on or off.  For example, the
.q ask
option informs
.i Mail
that each time you send a message, you want it to prompt you for
a subject header, to be included in the message.
To set the
.q ask
option, you would type
.(l
set ask
.)l
.pp
Another useful
.i Mail
option is
.q hold.
Unless told otherwise,
.i Mail
moves the messages from your system mailbox to the file
.i mbox
in your home directory when you leave
.i Mail .
If you want
.i Mail
to keep your letters in the system mailbox instead, you can set the
.q hold
option.
.pp
Valued options are values which
.i Mail
uses to adapt to your tastes.  For example, the
.q SHELL
option tells
.i Mail
which shell you like to use, and is specified by
.(l
set SHELL=/bin/csh
.)l
for example.  Note that no spaces are allowed in
.q "SHELL=/bin/csh."
A complete list of the
.i Mail
options appears in section 5.
.pp
Another important valued option is
.q crt.
If you use a fast video terminal, you will find that when you
print long messages, they fly by too quickly for you to read them.
With the
.q crt
option, you can make
.i Mail
print any message larger than a given number of lines by sending
it through a paging program. This program is specified by the
valued option \fBPAGER\fP.
If \fBPAGER\fP is not set, a default paginator is used.
For example, most CRT users with 24-line screens should do:
.(l
set crt=24
.)l
to paginate messages that will not fit on their screens.
In the default state, \fImore\fP (default paginator) prints a screenful of
information, then types --More--.  Type a space to see the next screenful.
.pp
Another adaptation to user needs that
.i Mail
provides is that of
.i aliases .
An alias is simply a name which stands for one or more
real user names.
.i Mail
sent to an alias is really sent to the list of real users
associated with it.  For example, an alias can be defined for the
members of a project, so that you can send mail to the whole project
by sending mail to just a single name.  The
.b alias
command in
.i Mail
defines an alias.  Suppose that the users in a project are
named Sam, Sally, Steve, and Susan.  To define an alias called
.q project
for them, you would use the
.i Mail
command:
.(l
alias project sam sally steve susan
.)l
The
.b alias
command can also be used to provide a convenient name for someone
whose user name is inconvenient.  For example, if a user named
.q "Bob Anderson"
had the login name
.q anderson,"
you might want to use:
.(l
alias bob anderson
.)l
so that you could send mail to the shorter name,
.q bob.
.pp
While the
.b alias
and
.b set
commands allow you to customize
.i Mail ,
they have the drawback that they must be retyped each time you enter
.i Mail .
To make them more convenient to use,
.i Mail
always looks for two files when it is invoked.  It first reads
a system wide file
.q /usr/lib/Mail.rc,
then a user specific file,
.q .mailrc,
which is found in the user's home directory.
The system wide file
is maintained by the system administrator and
contains
.b set
commands that are applicable to all users of the system.
The
.q .mailrc
file is usually used by each user to set options the way he likes
and define individual aliases.
For example, my .mailrc file looks like this:
.(l
set ask nosave SHELL=/bin/csh
.)l
As you can see, it is possible to set many options in the
same
.b set
command.  The
.q nosave
option is described in section 5.
.pp
Mail aliasing is implemented
at the system-wide level
by the mail delivery
system
.i sendmail .
These aliases are stored in the file /usr/lib/aliases and are
accessible to all users of the system.
The lines in /usr/lib/aliases are of
the form:
.(l
alias: name\*<1\*>, name\*<2\*>, name\*<3\*>
.)l
where
.i alias
is the mailing list name and the
.i name\*<i\*>
are the members of the list.  Long lists can be continued onto the next
line by starting the next line with a space or tab.  Remember that you
must execute the shell command
.i newaliases
after editing /usr/lib/aliases since the delivery system
uses an indexed file created by
.i newaliases .
.pp
We have seen that
.i Mail
can be invoked with command line arguments which are people
to send the message to, or with no arguments to read mail.
Specifying the
.rb \-f
flag on the command line causes
.i Mail
to read messages from a file other than your system mailbox.
For example, if you have a collection of messages in
the file
.q letters
you can use
.i Mail
to read them with:
.(l
% Mail \-f letters
.)l
You can use all
the
.i Mail
commands described in this document to examine, modify, or delete
messages from your
.q letters
file, which will be rewritten when you leave
.i Mail
with the
.b quit
command described below.
.pp
Since mail that you read is saved in the file
.i mbox
in your home directory by default, you can read
.i mbox
in your home directory by using simply
.(l
% Mail \-f
.)l
.pp
Normally, messages that you examine using the
.b type
command are saved in the file
.q mbox
in your home directory if you leave
.i Mail
with the
.b quit
command described below.
If you wish to retain a message in your system mailbox
you can use the
.b preserve
command to tell
.i Mail
to leave it there.
The
.b preserve
command accepts a list of message numbers, just like
.b type
and may be abbreviated to
.b pre .
.pp
Messages in your system mailbox that you do not examine are
normally retained in your system mailbox automatically.
If you wish to have such a message saved in
.i mbox
without reading it, you may use the
.b mbox
command to have them so saved.  For example,
.(l
mbox 2
.)l
in our example would cause the second message (from sam)
to be saved in
.i mbox
when the
.b quit
command is executed.
.b Mbox
is also the way to direct messages to your
.i mbox
file if you have set the
.q hold
option described above.
.b Mbox
can be abbreviated to
.b mb .
.pp
When you have perused all the messages of interest, you can leave
.i Mail
with the
.b quit
command, which saves the messages you have typed but not
deleted in the file
.i mbox
in your login directory.  Deleted messages are discarded irretrievably,
and messages left untouched are preserved in your system mailbox so
that you will see them the next time you type:
.(l
% Mail
.)l
The
.b quit
command can be abbreviated to simply
.b q .
.pp
If you wish for some reason to leave
.i Mail
quickly without altering either your system mailbox or
.i mbox ,
you can type the
.b x
command (short for
.b exit ),
which will immediately return you to the Shell without changing anything.
.pp
If, instead, you want to execute a Shell command without leaving
.i Mail ,
you
can type the command preceded by an exclamation point, just as in the
text editor.  Thus, for instance:
.(l
!date
.)l
will print the current date without leaving
.i Mail .
.pp
Finally, the
.b help
command is available to print out a brief summary of the
.i Mail
commands, using only the single character command abbreviations.