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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2003 The Open Group, All Rights Reserved --><title>write</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="write"></a> <a name="tag_04_172"></a><!-- write --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_04_172_01"></a>NAME</h4><blockquote>write - write to another user</blockquote><h4><a name="tag_04_172_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('UP')">UP</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> write</tt> <i>user_name</i> <b>[</b><i>terminal</i><b>]</b><tt><img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div></blockquote><h4><a name="tag_04_172_03"></a>DESCRIPTION</h4><blockquote><p>The <i>write</i> utility shall read lines from the user's standard input and write them to the terminal of another user. Whenfirst invoked, it shall write the message:</p><pre><b>Message from</b> <i>sender-login-id</i> <tt>(</tt><i>sending-terminal</i><tt>)</tt> <b>[</b><i>date</i><b>]</b><tt>...</tt></pre><p>to <i>user_name</i>. When it has successfully completed the connection, the sender's terminal shall be alerted twice to indicatethat what the sender is typing is being written to the recipient's terminal.</p><p>If the recipient wants to reply, this can be accomplished by typing:</p><pre><tt>write</tt> <i>sender-login-id</i> <b>[</b><i>sending-terminal</i><b>]</b></pre><p>upon receipt of the initial message. Whenever a line of input as delimited by an NL, EOF, or EOL special character (see the BaseDefinitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap11.html#tag_11">Chapter 11, General TerminalInterface</a>) is accumulated while in canonical input mode, the accumulated data shall be written on the other user's terminal.Characters shall be processed as follows:</p><ul><li><p>Typing <alert> shall write the alert character to the recipient's terminal.</p></li><li><p>Typing the erase and kill characters shall affect the sender's terminal in the manner described by the <b>termios</b> interfacein the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap11.html#tag_11">Chapter 11, GeneralTerminal Interface</a>.</p></li><li><p>Typing the interrupt or end-of-file characters shall cause <i>write</i> to write an appropriate message ( <tt>"EOT\n"</tt> inthe POSIX locale) to the recipient's terminal and exit.</p></li><li><p>Typing characters from <i>LC_CTYPE</i> classifications <b>print</b> or <b>space</b> shall cause those characters to be sent tothe recipient's terminal.</p></li><li><p>When and only when the <a href="../utilities/stty.html"><i>stty</i></a> <b>iexten</b> local mode is enabled, the existence andprocessing of additional special control characters and multi-byte or single-byte functions is implementation-defined.</p></li><li><p>Typing other non-printable characters shall cause implementation-defined sequences of printable characters to be written to therecipient's terminal.</p></li></ul><p>To write to a user who is logged in more than once, the <i>terminal</i> argument can be used to indicate which terminal to writeto; otherwise, the recipient's terminal is selected in an implementation-defined manner and an informational message is written tothe sender's standard output, indicating which terminal was chosen.</p><p>Permission to be a recipient of a <i>write</i> message can be denied or granted by use of the <a href="../utilities/mesg.html"><i>mesg</i></a> utility. However, a user's privilege may further constrain the domain of accessibility ofother users' terminals. The <i>write</i> utility shall fail when the user lacks the appropriate privileges to perform the requestedaction.</p></blockquote><h4><a name="tag_04_172_04"></a>OPTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_172_05"></a>OPERANDS</h4><blockquote><p>The following operands shall be supported:</p><dl compact><dt><i>user_name</i></dt><dd>Login name of the person to whom the message shall be written. The application shall ensure that this operand is of the formreturned by the <a href="../utilities/who.html"><i>who</i></a> utility.</dd><dt><i>terminal</i></dt><dd>Terminal identification in the same format provided by the <a href="../utilities/who.html"><i>who</i></a> utility.</dd></dl></blockquote><h4><a name="tag_04_172_06"></a>STDIN</h4><blockquote><p>Lines to be copied to the recipient's terminal are read from standard input.</p></blockquote><h4><a name="tag_04_172_07"></a>INPUT FILES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_172_08"></a>ENVIRONMENT VARIABLES</h4><blockquote><p>The following environment variables shall affect the execution of <i>write</i>:</p><dl compact><dt><i>LANG</i></dt><dd>Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap08.html#tag_08_02">Section 8.2, Internationalization Variables</a> forthe precedence of internationalization variables used to determine the values of locale categories.)</dd><dt><i>LC_ALL</i></dt><dd>If set to a non-empty string value, override the values of all the other internationalization variables.</dd><dt><i>LC_CTYPE</i></dt><dd>Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte asopposed to multi-byte characters in arguments and input files). If the recipient's locale does not use an <i>LC_CTYPE</i>equivalent to the sender's, the results are undefined.</dd><dt><i>LC_MESSAGES</i></dt><dd>Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error andinformative messages written to standard output.</dd><dt><i>NLSPATH</i></dt><dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">Determine the location of message catalogs for the processing of <i>LC_MESSAGES .</i> <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd></dl></blockquote><h4><a name="tag_04_172_09"></a>ASYNCHRONOUS EVENTS</h4><blockquote><p>If an interrupt signal is received, <i>write</i> shall write an appropriate message on the recipient's terminal and exit with astatus of zero. It shall take the standard action for all other signals.</p></blockquote><h4><a name="tag_04_172_10"></a>STDOUT</h4><blockquote><p>An informational message shall be written to standard output if a recipient is logged in more than once.</p></blockquote><h4><a name="tag_04_172_11"></a>STDERR</h4><blockquote><p>The standard error shall be used only for diagnostic messages.</p></blockquote><h4><a name="tag_04_172_12"></a>OUTPUT FILES</h4><blockquote><p>The recipient's terminal is used for output.</p></blockquote><h4><a name="tag_04_172_13"></a>EXTENDED DESCRIPTION</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_172_14"></a>EXIT STATUS</h4><blockquote><p>The following exit values shall be returned:</p><dl compact><dt> 0</dt><dd>Successful completion.</dd><dt>>0</dt><dd>The addressed user is not logged on or the addressed user denies permission.</dd></dl></blockquote><h4><a name="tag_04_172_15"></a>CONSEQUENCES OF ERRORS</h4><blockquote><p>Default.</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_04_172_16"></a>APPLICATION USAGE</h4><blockquote><p>The <a href="../utilities/talk.html"><i>talk</i></a> utility is considered by some users to be a more usable utility onfull-screen terminals.</p></blockquote><h4><a name="tag_04_172_17"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_172_18"></a>RATIONALE</h4><blockquote><p>The <i>write</i> utility was included in this volume of IEEE Std 1003.1-2001 since it can be implemented on allterminal types. The standard developers considered the <a href="../utilities/talk.html"><i>talk</i></a> utility, which cannot beimplemented on certain terminals, to be a "better" communications interface. Both of these programs are in widespread use onhistorical implementations. Therefore, the standard developers decided that both utilities should be specified.</p><p>The format of the terminal name is unspecified, but the descriptions of <a href="../utilities/ps.html"><i>ps</i></a>, <a href="../utilities/talk.html"><i>talk</i></a>, <a href="../utilities/who.html"><i>who</i></a>, and <i>write</i> require that they alluse or accept the same format.</p></blockquote><h4><a name="tag_04_172_19"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_172_20"></a>SEE ALSO</h4><blockquote><p><a href="mesg.html"><i>mesg</i></a> , <a href="talk.html"><i>talk</i></a> , <a href="who.html"><i>who</i></a> , the BaseDefinitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap11.html#tag_11">Chapter 11, General TerminalInterface</a></p></blockquote><h4><a name="tag_04_172_21"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 2.</p></blockquote><h4><a name="tag_04_172_22"></a>Issue 5</h4><blockquote><p>The FUTURE DIRECTIONS section is added.</p></blockquote><h4><a name="tag_04_172_23"></a>Issue 6</h4><blockquote><p>This utility is marked as part of the User Portability Utilities option.</p><p>The normative text is reworded to avoid use of the term "must" for application requirements.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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