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24 <center><font size="2">The Open Group Base Specifications Issue 8<br>
25 IEEE Std 1003.1-2024<br>
26 Copyright © 2001-2024 The IEEE and The Open Group</font></center>
27 <hr size="2" noshade>
28 <a name="top" id="top"></a> <a name="strings" id="strings"></a> <a name="tag_20_114" id="tag_20_114"></a><!-- strings -->
29 <h4 class="mansect"><a name="tag_20_114_01" id="tag_20_114_01"></a>NAME</h4>
30 <blockquote>strings — find printable strings in files</blockquote>
31 <h4 class="mansect"><a name="tag_20_114_02" id="tag_20_114_02"></a>SYNOPSIS</h4>
32 <blockquote class="synopsis">
33 <p><code><tt>strings</tt> <b>[</b><tt>-a</tt><b>] [</b><tt>-t</tt> <i>format</i><b>] [</b><tt>-n</tt> <i>number</i><b>]
34 [</b><i>file</i><tt>...</tt><b>]</b></code></p>
35 </blockquote>
36 <h4 class="mansect"><a name="tag_20_114_03" id="tag_20_114_03"></a>DESCRIPTION</h4>
37 <blockquote>
38 <p>The <i>strings</i> utility shall look for printable strings in regular files and shall write those strings to standard output. A
39 printable string is any sequence of four (by default) or more printable characters terminated by a <newline> or NUL
40 character. Additional implementation-defined strings may be written; see <a href=
41 "../utilities/localedef.html"><i>localedef</i></a>.</p>
42 <p>If any argument is <tt>'-'</tt>, the results are unspecified.</p>
43 </blockquote>
44 <h4 class="mansect"><a name="tag_20_114_04" id="tag_20_114_04"></a>OPTIONS</h4>
45 <blockquote>
46 <p>The <i>strings</i> utility shall conform to XBD <a href="../basedefs/V1_chap12.html#tag_12_02"><i>12.2 Utility Syntax
47 Guidelines</i></a> , except for the unspecified usage of <tt>'-'</tt>.</p>
48 <p>The following options shall be supported:</p>
49 <dl compact>
50 <dd></dd>
51 <dt><b>-a</b></dt>
52 <dd>Scan files in their entirety. If <b>-a</b> is not specified, it is implementation-defined what portion of each file is scanned
53 for strings.</dd>
54 <dt><b>-n </b><i>number</i></dt>
55 <dd>Specify the minimum string length, where the <i>number</i> argument is a positive decimal integer. The default shall be 4.</dd>
56 <dt><b>-t </b><i>format</i></dt>
57 <dd>Write each string preceded by its byte offset from the start of the file. The format shall be dependent on the single character
58 used as the <i>format</i> option-argument:
59 <dl compact>
60 <dd></dd>
61 <dt><tt>d</tt></dt>
62 <dd>The offset shall be written in decimal.</dd>
63 <dt><tt>o</tt></dt>
64 <dd>The offset shall be written in octal.</dd>
65 <dt><tt>x</tt></dt>
66 <dd>The offset shall be written in hexadecimal.</dd>
67 </dl>
68 </dd>
69 </dl>
70 </blockquote>
71 <h4 class="mansect"><a name="tag_20_114_05" id="tag_20_114_05"></a>OPERANDS</h4>
72 <blockquote>
73 <p>The following operand shall be supported:</p>
74 <dl compact>
75 <dd></dd>
76 <dt><i>file</i></dt>
77 <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 read
78 from the standard input.</dd>
79 </dl>
80 </blockquote>
81 <h4 class="mansect"><a name="tag_20_114_06" id="tag_20_114_06"></a>STDIN</h4>
82 <blockquote>
83 <p>See the INPUT FILES section.</p>
84 </blockquote>
85 <h4 class="mansect"><a name="tag_20_114_07" id="tag_20_114_07"></a>INPUT FILES</h4>
86 <blockquote>
87 <p>The input files named by the utility arguments or the standard input shall be regular files of any format.</p>
88 </blockquote>
89 <h4 class="mansect"><a name="tag_20_114_08" id="tag_20_114_08"></a>ENVIRONMENT VARIABLES</h4>
90 <blockquote>
91 <p>The following environment variables shall affect the execution of <i>strings</i>:</p>
92 <dl compact>
93 <dd></dd>
94 <dt><i>LANG</i></dt>
95 <dd>Provide a default value for the internationalization variables that are unset or null. (See XBD <a href=
96 "../basedefs/V1_chap08.html#tag_08_02"><i>8.2 Internationalization Variables</i></a> for the precedence of internationalization
97 variables used to determine the values of locale categories.)</dd>
98 <dt><i>LC_ALL</i></dt>
99 <dd>If set to a non-empty string value, override the values of all the other internationalization variables.</dd>
100 <dt><i>LC_CTYPE</i></dt>
101 <dd>Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as
102 opposed to multi-byte characters in arguments and input files) and to identify printable strings.</dd>
103 <dt><i>LC_MESSAGES</i></dt>
104 <dd><br>
105 Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.</dd>
106 <dt><i>NLSPATH</i></dt>
107 <dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
108 Determine the location of messages objects and message catalogs. <img src="../images/opt-end.gif" alt="[Option End]" border=
109 "0"></dd>
110 </dl>
111 </blockquote>
112 <h4 class="mansect"><a name="tag_20_114_09" id="tag_20_114_09"></a>ASYNCHRONOUS EVENTS</h4>
113 <blockquote>
114 <p>Default.</p>
115 </blockquote>
116 <h4 class="mansect"><a name="tag_20_114_10" id="tag_20_114_10"></a>STDOUT</h4>
117 <blockquote>
118 <p>Strings found shall be written to the standard output, one per line.</p>
119 <p>When the <b>-t</b> option is not specified, the format of the output shall be:</p>
120 <pre>
121 <tt>"%s", <</tt><i>string</i><tt>>
122 </tt></pre>
123 <p>With the <b>-t o</b> option, the format of the output shall be:</p>
124 <pre>
125 <tt>"%o %s", <</tt><i>byte offset</i><tt>>, <</tt><i>string</i><tt>>
126 </tt></pre>
127 <p>With the <b>-t x</b> option, the format of the output shall be:</p>
128 <pre>
129 <tt>"%x %s", <</tt><i>byte offset</i><tt>>, <</tt><i>string</i><tt>>
130 </tt></pre>
131 <p>With the <b>-t d</b> option, the format of the output shall be:</p>
132 <pre>
133 <tt>"%d %s", <</tt><i>byte offset</i><tt>>, <</tt><i>string</i><tt>>
134 </tt></pre></blockquote>
135 <h4 class="mansect"><a name="tag_20_114_11" id="tag_20_114_11"></a>STDERR</h4>
136 <blockquote>
137 <p>The standard error shall be used only for diagnostic messages.</p>
138 </blockquote>
139 <h4 class="mansect"><a name="tag_20_114_12" id="tag_20_114_12"></a>OUTPUT FILES</h4>
140 <blockquote>
141 <p>None.</p>
142 </blockquote>
143 <h4 class="mansect"><a name="tag_20_114_13" id="tag_20_114_13"></a>EXTENDED DESCRIPTION</h4>
144 <blockquote>
145 <p>None.</p>
146 </blockquote>
147 <h4 class="mansect"><a name="tag_20_114_14" id="tag_20_114_14"></a>EXIT STATUS</h4>
148 <blockquote>
149 <p>The following exit values shall be returned:</p>
150 <dl compact>
151 <dd></dd>
152 <dt> 0</dt>
153 <dd>Successful completion.</dd>
154 <dt>>0</dt>
155 <dd>An error occurred.</dd>
156 </dl>
157 </blockquote>
158 <h4 class="mansect"><a name="tag_20_114_15" id="tag_20_114_15"></a>CONSEQUENCES OF ERRORS</h4>
159 <blockquote>
160 <p>Default.</p>
161 </blockquote>
162 <hr>
163 <div class="box"><em>The following sections are informative.</em></div>
164 <h4 class="mansect"><a name="tag_20_114_16" id="tag_20_114_16"></a>APPLICATION USAGE</h4>
165 <blockquote>
166 <p>By default the data area (as opposed to the text, "bss", or header areas) of a binary executable file is scanned.
167 Implementations document which areas are scanned.</p>
168 <p>Some historical implementations do not require NUL or <newline> terminators for strings to permit those languages that do
169 not use NUL as a string terminator to have their strings written.</p>
170 </blockquote>
171 <h4 class="mansect"><a name="tag_20_114_17" id="tag_20_114_17"></a>EXAMPLES</h4>
172 <blockquote>
173 <p>None.</p>
174 </blockquote>
175 <h4 class="mansect"><a name="tag_20_114_18" id="tag_20_114_18"></a>RATIONALE</h4>
176 <blockquote>
177 <p>Apart from rationalizing the option syntax and slight difficulties with object and executable binary files, <i>strings</i> is
178 specified to match historical practice closely. The <b>-a</b> and <b>-n</b> options were introduced to replace the non-conforming
179 <b>-</b> and <b>-</b><i>number</i> options. These options are no longer specified by POSIX.1-2024 but may be present in some
180 implementations.</p>
181 <p>The <b>-o</b> option historically means different things on different implementations. Some use it to mean "<i>offset</i> in
182 decimal", while others use it as "<i>offset</i> in octal". Instead of trying to decide which way would be least objectionable,
183 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 consistent
184 with <a href="../utilities/od.html"><i>od</i></a>.</p>
185 <p>The ISO C standard function <a href="../functions/isprint.html"><i>isprint</i>()</a> is restricted to a domain of
186 <b>unsigned char</b>. This volume of POSIX.1-2024 requires implementations to write strings as defined by the current locale.</p>
187 </blockquote>
188 <h4 class="mansect"><a name="tag_20_114_19" id="tag_20_114_19"></a>FUTURE DIRECTIONS</h4>
189 <blockquote>
190 <p>None.</p>
191 </blockquote>
192 <h4 class="mansect"><a name="tag_20_114_20" id="tag_20_114_20"></a>SEE ALSO</h4>
193 <blockquote>
194 <p><a href="../utilities/localedef.html#"><i>localedef</i></a> , <a href="../utilities/nm.html#"><i>nm</i></a></p>
195 <p>XBD <a href="../basedefs/V1_chap08.html#tag_08"><i>8. Environment Variables</i></a> , <a href=
196 "../basedefs/V1_chap12.html#tag_12_02"><i>12.2 Utility Syntax Guidelines</i></a></p>
197 </blockquote>
198 <h4 class="mansect"><a name="tag_20_114_21" id="tag_20_114_21"></a>CHANGE HISTORY</h4>
199 <blockquote>
200 <p>First released in Issue 4.</p>
201 </blockquote>
202 <h4 class="mansect"><a name="tag_20_114_22" id="tag_20_114_22"></a>Issue 6</h4>
203 <blockquote>
204 <p>This utility is marked as part of the User Portability Utilities option.</p>
205 <p>The obsolescent SYNOPSIS is removed.</p>
206 <p>The normative text is reworded to avoid use of the term "must" for application requirements.</p>
207 </blockquote>
208 <h4 class="mansect"><a name="tag_20_114_23" id="tag_20_114_23"></a>Issue 7</h4>
209 <blockquote>
210 <p>Austin Group Interpretation 1003.1-2001 #027 is applied, clarifying the behavior if the first argument is <tt>'-'</tt>.</p>
211 <p>The <i>strings</i> utility is moved from the User Portability Utilities option to the Base. User Portability Utilities is now an
212 option for interactive utilities.</p>
213 <p>SD5-XCU-ERN-97 is applied, updating the SYNOPSIS.</p>
214 </blockquote>
215 <h4 class="mansect"><a name="tag_20_114_24" id="tag_20_114_24"></a>Issue 8</h4>
216 <blockquote>
217 <p>Austin Group Defect 1122 is applied, changing the description of <i>NLSPATH .</i></p>
218 <p>Austin Group Defect 1599 is applied, making the behavior unspecified when any argument is <tt>'-'</tt>.</p>
219 </blockquote>
220 <div class="box"><em>End of informative text.</em></div>
221 <hr>
222 <p> </p>
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