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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>expand</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="expand"></a> <a name="tag_04_48"></a><!-- expand --> <!--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_48_01"></a>NAME</h4><blockquote>expand - convert tabs to spaces</blockquote><h4><a name="tag_04_48_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"> expand</tt> <b>[</b><tt>-t</tt> <i>tablist</i><b>][</b><i>file</i> <tt>...</tt><b>]</b><tt><img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div></blockquote><h4><a name="tag_04_48_03"></a>DESCRIPTION</h4><blockquote><p>The <i>expand</i> utility shall write files or the standard input to the standard output with <tab>s replaced with one ormore <space>s needed to pad to the next tab stop. Any <backspace>s shall be copied to the output and cause the columnposition count for tab stop calculations to be decremented; the column position count shall not be decremented below zero.</p></blockquote><h4><a name="tag_04_48_04"></a>OPTIONS</h4><blockquote><p>The <i>expand</i> utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap12.html#tag_12_02">Section 12.2, Utility Syntax Guidelines</a>.</p><p>The following option shall be supported:</p><dl compact><dt><b>-t </b> <i>tablist</i></dt><dd>Specify the tab stops. The application shall ensure that the argument <i>tablist</i> consists of either a single positivedecimal integer or a list of tabstops. If a single number is given, tabs shall be set that number of column positions apart insteadof the default 8. <p>If a list of tabstops is given, the application shall ensure that it consists of a list of two or more positive decimalintegers, separated by <blank>s or commas, in ascending order. The tabs shall be set at those specific column positions. Eachtab stop <i>N</i> shall be an integer value greater than zero, and the list is in strictly ascending order. This is taken to meanthat, from the start of a line of output, tabbing to position <i>N</i> shall cause the next character output to be in the (<i>N</i>+1)th column position on that line.</p><p>In the event of <i>expand</i> having to process a <tab> at a position beyond the last of those specified in a multipletab-stop list, the <tab> shall be replaced by a single <space> in the output.</p></dd></dl></blockquote><h4><a name="tag_04_48_05"></a>OPERANDS</h4><blockquote><p>The following operand shall be supported:</p><dl compact><dt><i>file</i></dt><dd>The pathname of a text file to be used as input.</dd></dl></blockquote><h4><a name="tag_04_48_06"></a>STDIN</h4><blockquote><p>See the INPUT FILES section.</p></blockquote><h4><a name="tag_04_48_07"></a>INPUT FILES</h4><blockquote><p>Input files shall be text files.</p></blockquote><h4><a name="tag_04_48_08"></a>ENVIRONMENT VARIABLES</h4><blockquote><p>The following environment variables shall affect the execution of <i>expand</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), the processing of <tab>s and <space>s, and for thedetermination of the width in column positions each character would occupy on an output device.</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 standarderror.</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_48_09"></a>ASYNCHRONOUS EVENTS</h4><blockquote><p>Default.</p></blockquote><h4><a name="tag_04_48_10"></a>STDOUT</h4><blockquote><p>The standard output shall be equivalent to the input files with <tab>s converted into the appropriate number of<space>s.</p></blockquote><h4><a name="tag_04_48_11"></a>STDERR</h4><blockquote><p>The standard error shall be used only for diagnostic messages.</p></blockquote><h4><a name="tag_04_48_12"></a>OUTPUT FILES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_48_13"></a>EXTENDED DESCRIPTION</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_48_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>An error occurred.</dd></dl></blockquote><h4><a name="tag_04_48_15"></a>CONSEQUENCES OF ERRORS</h4><blockquote><p>The <i>expand</i> utility shall terminate with an error message and non-zero exit status upon encountering difficultiesaccessing one of the <i>file</i> operands.</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_04_48_16"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_48_17"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_48_18"></a>RATIONALE</h4><blockquote><p>The <i>expand</i> utility is useful for preprocessing text files (before sorting, looking at specific columns, and so on) thatcontain <tab>s.</p><p>See the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap03.html#tag_03_103">Section3.103, Column Position</a>.</p><p>The <i>tablist</i> option-argument consists of integers in ascending order. Utility Syntax Guideline 8 mandates that<i>expand</i> shall accept the integers (within the single argument) separated using either commas or <blank>s.</p></blockquote><h4><a name="tag_04_48_19"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_48_20"></a>SEE ALSO</h4><blockquote><p><a href="tabs.html"><i>tabs</i></a> , <a href="unexpand.html"><i>unexpand</i></a></p></blockquote><h4><a name="tag_04_48_21"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 4.</p></blockquote><h4><a name="tag_04_48_22"></a>Issue 6</h4><blockquote><p>This utility is marked as part of the User Portability Utilities option.</p><p>The APPLICATION USAGE section is added.</p><p>The obsolescent SYNOPSIS is removed.</p><p>The <i>LC_CTYPE</i> environment variable description is updated to align with the IEEE P1003.2b draft standard.</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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