mailx.html

unix 下的C开发手册,还用详细的例程。

If the
<b>toplines</b>
variable is set,
it is taken as the number of lines to write.
The default is 5.
<h5><a name = "tag_001_014_1358_039">&nbsp;</a>Touch Messages</h5>
<i>Synopsis</i>:   
tou<b>[</b>ch<b>]</b> <b>[</b><i>msglist</i><b>]</b>
<p>
Touch the specified messages.
If any message in
<i>msglist</i>
is not specifically deleted nor saved in a file,
it will be placed in the
<b>mbox</b>
upon normal termination.
See
<b>exit</b>
and
<b>quit</b>.
<h5><a name = "tag_001_014_1358_040">&nbsp;</a>Delete Aliases</h5>
<i>Synopsis</i>:   
una<b>[</b>lias<b>]</b> <b>[</b><i>alias</i><b>]</b>...
<p>
Delete the specified alias names.
If a specified alias does not exist, the results are unspecified.
<h5><a name = "tag_001_014_1358_041">&nbsp;</a>Undelete Messages</h5>
<i>Synopsis</i>:   
u<b>[</b>ndelete<b>]</b> <b>[</b><i>msglist</i><b>]</b>
<p>
Remove the deleted markings from the specified messages.
If
<b>autoprint</b>
is set, the last message of those restored
will be written.
If
<i>msglist</i>
is not specified, it defaults to the first deleted message
following the current message that has not been undeleted if there is
one, or the last deleted message preceding the current message that
has not been undeleted otherwise.
<h5><a name = "tag_001_014_1358_042">&nbsp;</a>Unset Variables</h5>
<i>Synopsis</i>:   
uns<b>[</b>et<b>]</b><i> name</i>...
<p>
Cause the specified variables to be erased.
<h5><a name = "tag_001_014_1358_043">&nbsp;</a>Edit Message with Full-screen Editor</h5>
<i>Synopsis</i>:   
v<b>[</b>isual<b>] [</b><i>msglist</i><b>]</b>
<p>
Edit the given messages with a screen editor.
The messages are placed in a temporary file, and the
utility named by the
<i>VISUAL</i>
variable
will be invoked to edit the file.
The default editor is
<i><a href="vi.html">vi</a></i>.
<p>
The
<b>visual</b>
command merely edits the specified messages in a temporary file.
It does not modify the contents of those messages in the mailbox.
<h5><a name = "tag_001_014_1358_044">&nbsp;</a>Write Messages to a File</h5>
<i>Synopsis</i>:   
w<b>[</b>rite<b>]</b> <b>[</b><i>msglist</i><b>] </b><i>file</i>
<p>
<br>
Write the given messages to the file specified by the pathname
<i>file</i>,
minus the message header.
Otherwise, it is equivalent to the
<b>save</b>
command.
<h5><a name = "tag_001_014_1358_045">&nbsp;</a>Scroll Header Display</h5>
<i>Synopsis</i>:   
z<b>[</b>+|-<b>]</b>
<p>
Scroll the header display forward (if "+"
is specified or if no option is
specified) or backward (if "-" is specified) one screenful.
The number of headers written is set by the
<b>screen</b>
variable.
<h5><a name = "tag_001_014_1358_046">&nbsp;</a>Invoke Shell Command</h5>
<i>Synopsis</i>:   
!<i>command</i>
<p>
Invoke the command interpreter specified by
<i>SHELL</i>
with two arguments:
<b>-c</b>
and
<i>command</i>.
(See also
<i><a href="sh.html">sh</a></i>
<b>-c</b>.)
If the
<b>bang</b>
variable is set, each unescaped occurrence of
"!"
in command
is replaced with the command executed by the previous
"!"
command or
~!
command escape.
<h5><a name = "tag_001_014_1358_047">&nbsp;</a>Null Command</h5>
<i>Synopsis</i>:   
# <i>comment</i>
<p>
This null command (comment) will be ignored by
<i>mailx</i>.
<h5><a name = "tag_001_014_1358_048">&nbsp;</a>Display Current Message Number</h5>
<i>Synopsis</i>:   
=
<p>
Write the current message number.
<h5><a name = "tag_001_014_1358_049">&nbsp;</a>Command Escapes in mailx</h5>
<xref type="5" name="mxcmdesc"></xref>
The following commands can be entered only from
input mode,
by beginning a line with the escape character
(by default, tilde
(~)).
See the
<b>escape</b>
variable description
for changing this special character.
The format for the commands is:
<pre>
<dl compact><dt> <dd>
&lt;ESC&gt;&lt;<i>command-char</i>&gt;&lt;<i>separator</i>&gt;<b>[</b>&lt;<i>arguments</i>&gt;<b>]</b>
</dl>
</pre>
where the
&lt;<i>separator</i>&gt;
can be zero or more
blank characters.
<p>
In the following descriptions, the argument
<i>command</i>
(but not
<i>mailx-command)</i>
must be a shell command string.
Any string acceptable
to the command interpreter specified by the
<i>SHELL</i>
variable
when it is invoked as
<b>-c</b>
<i>command_string</i>
is valid.
The command can be presented as multiple arguments (that is,
quoting is not required).
<p>
Command escapes that are listed with
<i>msglist</i>
or
<i>mailx-command</i>
arguments are invalid in Send Mode
and produce unspecified results.
<dl compact>

<dt><b>~!</b> <i>command</i><dd>
Invoke the command interpreter specified by
<i>SHELL</i>
with two arguments:
<b>-c</b>
and
<i>command</i>;
and then return to input mode.
If the
<b>bang</b>
variable is set, each unescaped occurrence of
"!"
in
<i>command</i>
is replaced with the command executed by the previous
"!"
command or
~!
command escape.

<dt><b>~.</b><dd>Simulate end-of-file (terminate message input).


<dt><b>~:</b> <i>mailx-command</i><dd>
<dt><b>~_ </b><i>mailx-command</i><dd>
Perform the command-level request.

<dt><b>~?</b><dd>Write a summary of command escapes.

<dt><b>~A</b><dd>This is equivalent to
i<b>Sign</b>.

<dt><b>~a</b><dd>This is equivalent to
i<b>sign</b>.

<dt><b>~b</b> <i>name...</i><dd>
Add the
<i>name</i>s to the blind carbon copy (Bcc) list.

<dt><b>~c</b> <i>name...</i><dd>
Add the
<i>name</i>s to the carbon copy (Cc) list.

<dt><b>~d</b><dd>Read in the dead-letter file.
See
<i>DEAD</i>
for a description of this file.

<dt><b>~e</b><dd>Invoke the editor,
as specified by the
<i>EDITOR</i>
environment variable,
on the partial message.

<dt><b>~f</b> <b>[</b><i>msglist</i><b>]</b><dd>
Forward the specified messages.
The specified messages will be inserted into the current
message without alteration.
This command escape will also insert message headers
into the message with field selection affected by the
<b>discard</b>,
<b>ignore</b>
and
<b>retain</b>
commands.

<dt><b>~F</b> <b>[</b><i>msglist</i><b>]</b><dd>
This will be the equivalent of the
<b>~f</b>
command escape, except that all headers
will be included in the message,
regardless of previous
<b>discard</b>,
<b>ignore</b>
and
<b>retain</b>
commands.

<dt><b>~h</b><dd>If standard input is a terminal,
prompt for a Subject line and the To, Cc and Bcc lists.
Other implementation-dependent
headers may also be presented for editing.
If the field is written with an initial value,
it can be edited as if it had just been typed.

<dt><b>~i</b> <i>string</i><dd>Insert the value of the named variable, followed by a
newline character,
into the text of the message.
If the string is unset or null, the message will not be changed.

<dt><b>~m</b> <b>[</b><i>msglist</i><b>]</b><dd>
Insert the specified messages into the message,
prefixing non-empty lines with the string in the
<b>indentprefix</b>
variable.
This command escape will also insert message headers
into the message, with field selection affected by the
<b>discard</b>,
<b>ignore</b>
and
<b>retain</b>
commands.

<dt><b>~M</b> <b>[</b><i>msglist</i><b>]</b><dd>
This will be the equivalent of the
<b>~m</b>
command escape, except that all headers
will be included in the message,
regardless of previous
<b>discard</b>,
<b>ignore</b>
and
<b>retain</b>
commands.


<dt><b>~p</b><dd>Write the message being entered.
If the message is longer than
<b>crt</b>
lines (see
<xref href=mxintv><a href="#tag_001_014_1358_002">
Internal Variables in mailx
</a></xref>),
the output will be paginated as described for the
<i>PAGER</i>
variable.

<dt><b>~q</b><dd>Quit (see the
<b>quit</b>
command) from input mode by simulating an interrupt.
If the body of the message is not empty,
the partial message will be saved in
the dead-letter file.
See
<i>DEAD</i>
for a description of this file.


<dt><b>~r</b> <i>file</i><dd>
<dt><b>~&lt; </b><i>file</i><dd>
<dt><b>~&lt; !</b><i>command</i><dd>
Read in the file specified by the pathname
<i>file</i>.
If the argument begins with an exclamation-mark
(!),
the rest of the string is taken as an arbitrary system command;
the command interpreter specified by
<i>SHELL</i>
will be invoked with two arguments:
<b>-c</b>
and
<i>command</i>.
The standard output of
<i>command</i>
will be inserted into the message.

<dt><b>~s</b>&nbsp;<i>string</i><dd>Set the subject line to
<i>string</i>.

<dt><b>~t</b> <i>name...</i><dd>
Add the given
<i>name</i>s to the To list.

<dt><b>~v</b><dd>Invoke the full-screen editor,
as specified by the
<i>VISUAL</i>
environment variable,
on the partial message.

<dt><b>~w</b> <i>file</i><dd>Write the partial message,
without the header,
onto the file named by the pathname
<i>file</i>.
The file will be created or the message will be appended
to it if the file exists.

<dt><b>~x</b><dd>Exit as with
<b>~q</b>,
except the message will not be saved in
the dead-letter file.


<dt><b>~| </b><i>command</i><dd>
Pipe the body of the message through the given
<i>command</i>
by invoking the command interpreter specified by
<i>SHELL</i>
with two arguments:
<b>-c</b>
and
<i>command</i>.
If the
<i>command</i>
returns a successful exit status,
the standard output of the command will replace the message.
Otherwise the message will remain unchanged.
If the
<i>command</i>
fails, an error message giving the exit status will be written.

</dl>
</blockquote><h4><a name = "tag_001_014_1359">&nbsp;</a>EXIT STATUS</h4><blockquote>
When the
<b>-e</b>
option is specified, the
following exit values are returned:
<dl compact>

<dt>0<dd>Mail was found.

<dt>&gt;0<dd>Mail was not found or an error occurred.

</dl>
<p>
Otherwise,
the following exit values are returned:
<dl compact>

<dt>0<dd>Successful completion;
note that this status implies that all messages were
<i>sent ,</i>
but it gives no assurances that any of them were actually
<i>delivered.</i>

<dt>&gt;0<dd>An error occurred.

</dl>
</blockquote><h4><a name = "tag_001_014_1360">&nbsp;</a>CONSEQUENCES OF ERRORS</h4><blockquote>
When in input mode (Receive Mode) or Send Mode:
<ul>
<p>
<li>
If an error is encountered processing a command escape (see
<xref href=mxcmdesc><a href="#tag_001_014_1358_049">
Command Escapes in mailx
</a></xref>),
a diagnostic message will be written to standard error,
and the message being composed may be modified,
but this condition will not prevent the
message from being sent.
<p>
<li>
Other errors will prevent the sending of the message.
<p>
</ul>
<p>
When in command mode:
<ul>
<p>
<li>
Default.
<p>
</ul>
<br>
</blockquote><h4><a name = "tag_001_014_1361">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
Delivery of messages to remote systems requires the
existence of communication paths to such systems.
These need not exist.
<p>
Input lines are limited to
{LINE_MAX}
bytes, but mailers between systems
may impose more severe line-length restrictions.
This specification does not place any restrictions on the length of
messages handled by
<i>mailx</i>,
and for delivery of local messages
the only limitations should be the normal problems of available
disk space for the target mail file.
When sending messages to
external machines, applications are advised to limit messages to
less than 50 kilobytes because many
mail gateways impose message-length restrictions.
<p>
The format of the system mailbox is intentionally unspecified.
Not all systems will implement system mailboxes as flat files,
particularly with the advent of multimedia mail messages.
Some system mailboxes may be multiple files,
others records in a database.
The internal format of the messages themselves are specified
with the historical format from Version&nbsp;7, but only
after they have been saved in some file other than the
system mailbox.
This was done so that many historical applications
expecting text-file mailboxes will not be broken.
<p>
Some new formats for messages can be expected in the future,
probably including binary data, bit maps and various
multimedia objects.
As described here,
<i>mailx</i>
is not prohibited from handling such messages,
but it must store them as text files in secondary mailboxes
(unless some extension, such as a variable
or command-line option, is used to change the stored format).
Its method of doing so is implementation-dependent and might include
translating the data into text-file-compatible or readable form or
omitting certain portions of the message from the stored output.
<p>
The
<b>discard</b>
and
<b>ignore</b>
commands are not inverses of the
<b>retain</b>
command.
The
<b>retain</b>
command discards all header-fields except those explicitly retained.
The
<b>discard</b>
command keeps all header-fields except those
explicitly discarded.
If headers exist on the retained header list,
<b>discard</b>
and
<b>ignore</b>
commands are ignored.
</blockquote><h4><a name = "tag_001_014_1362">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1363">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
The IEEE PASC 1003.2 Interpretations Committee has forwarded concerns about
parts of this interface definition to the IEEE PASC Shell and Utilities Working Group
which is identifying the corrections.
A future revision of this specification will align with
IEEE Std. 1003.2b when finalised.
</blockquote><h4><a name = "tag_001_014_1364">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="ed.html">ed</a></i>,
<i><a href="ls.html">ls</a></i>,
<i><a href="mail.html">mail</a></i>,
<i><a href="more.html">more</a></i>,
<i><a href="vi.html">vi</a></i>.
<br>
</blockquote><hr size=2 noshade>
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Copyright &copy; 1997 The Open Group
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