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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) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>strings</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="strings"></a> <a name="tag_04_133"></a><!-- strings --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_04_133_01"></a>NAME</h4><blockquote>strings - find printable strings in files</blockquote><h4><a name="tag_04_133_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"> strings</tt> <b>[</b><tt>-a</tt><b>][</b><tt>-t</tt> <i>format</i><b>][</b><tt>-n</tt><i>number</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_133_03"></a>DESCRIPTION</h4><blockquote><p>The <i>strings</i> utility shall look for printable strings in regular files and shall write those strings to standard output. Aprintable string is any sequence of four (by default) or more printable characters terminated by a <newline> or NULcharacter. Additional implementation-defined strings may be written; see <a href="../utilities/localedef.html"><i>localedef</i></a>.</p></blockquote><h4><a name="tag_04_133_04"></a>OPTIONS</h4><blockquote><p>The <i>strings</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 options shall be supported:</p><dl compact><dt><b>-a</b></dt><dd>Scan files in their entirety. If <b>-a</b> is not specified, it is implementation-defined what portion of each file is scannedfor strings.</dd><dt><b>-n </b> <i>number</i></dt><dd>Specify the minimum string length, where the <i>number</i> argument is a positive decimal integer. The default shall be 4.</dd><dt><b>-t </b> <i>format</i></dt><dd>Write each string preceded by its byte offset from the start of the file. The format shall be dependent on the single characterused as the <i>format</i> option-argument: <dl compact><dt><tt>d</tt></dt><dd>The offset shall be written in decimal.</dd><dt><tt>o</tt></dt><dd>The offset shall be written in octal.</dd><dt><tt>x</tt></dt><dd>The offset shall be written in hexadecimal.</dd></dl></dd></dl></blockquote><h4><a name="tag_04_133_05"></a>OPERANDS</h4><blockquote><p>The following operand shall be supported:</p><dl compact><dt><i>file</i></dt><dd>A pathname of a regular file to be used as input. If no <i>file</i> operand is specified, the <i>strings</i> utility shall readfrom the standard input.</dd></dl></blockquote><h4><a name="tag_04_133_06"></a>STDIN</h4><blockquote><p>See the INPUT FILES section.</p></blockquote><h4><a name="tag_04_133_07"></a>INPUT FILES</h4><blockquote><p>The input files named by the utility arguments or the standard input shall be regular files of any format.</p></blockquote><h4><a name="tag_04_133_08"></a>ENVIRONMENT VARIABLES</h4><blockquote><p>The following environment variables shall affect the execution of <i>strings</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) and to identify printable strings.</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_133_09"></a>ASYNCHRONOUS EVENTS</h4><blockquote><p>Default.</p></blockquote><h4><a name="tag_04_133_10"></a>STDOUT</h4><blockquote><p>Strings found shall be written to the standard output, one per line.</p><p>When the <b>-t</b> option is not specified, the format of the output shall be:</p><pre><tt>"%s", <</tt><i>string</i><tt>></tt></pre><p>With the <b>-t o</b> option, the format of the output shall be:</p><pre><tt>"%o %s", <</tt><i>byte offset</i><tt>>, <</tt><i>string</i><tt>></tt></pre><p>With the <b>-t x</b> option, the format of the output shall be:</p><pre><tt>"%x %s", <</tt><i>byte offset</i><tt>>, <</tt><i>string</i><tt>></tt></pre><p>With the <b>-t d</b> option, the format of the output shall be:</p><pre><tt>"%d %s", <</tt><i>byte offset</i><tt>>, <</tt><i>string</i><tt>></tt></pre></blockquote><h4><a name="tag_04_133_11"></a>STDERR</h4><blockquote><p>The standard error shall be used only for diagnostic messages.</p></blockquote><h4><a name="tag_04_133_12"></a>OUTPUT FILES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_133_13"></a>EXTENDED DESCRIPTION</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_133_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_133_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_133_16"></a>APPLICATION USAGE</h4><blockquote><p>By default the data area (as opposed to the text, "bss", or header areas) of a binary executable file is scanned.Implementations document which areas are scanned.</p><p>Some historical implementations do not require NUL or <newline> terminators for strings to permit those languages that donot use NUL as a string terminator to have their strings written.</p></blockquote><h4><a name="tag_04_133_17"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_133_18"></a>RATIONALE</h4><blockquote><p>Apart from rationalizing the option syntax and slight difficulties with object and executable binary files, <i>strings</i> isspecified to match historical practice closely. The <b>-a</b> and <b>-n</b> options were introduced to replace the non-conforming<b>-</b> and <b>-</b> <i>number</i> options.</p><p>The <b>-o</b> option historically means different things on different implementations. Some use it to mean " <i>offset</i> indecimal", while others use it as " <i>offset</i> in octal". Instead of trying to decide which way would be least objectionable,the <b>-t</b> option was added. It was originally named <b>-O</b> to mean "offset", but was changed to <b>-t</b> to be consistentwith <a href="../utilities/od.html"><i>od</i></a>.</p><p>The ISO C standard function <a href="../functions/isprint.html"><i>isprint</i>()</a> is restricted to a domain of<b>unsigned char</b>. This volume of IEEE Std 1003.1-2001 requires implementations to write strings as defined by thecurrent locale.</p></blockquote><h4><a name="tag_04_133_19"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_133_20"></a>SEE ALSO</h4><blockquote><p><a href="localedef.html"><i>localedef</i></a>, <a href="nm.html"><i>nm</i></a></p></blockquote><h4><a name="tag_04_133_21"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 4.</p></blockquote><h4><a name="tag_04_133_22"></a>Issue 6</h4><blockquote><p>This utility is marked as part of the User Portability Utilities option.</p><p>The obsolescent SYNOPSIS is removed.</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 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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