详解linux中的strings命令简介

谭复喜 發表於 2024-4-11 00:00:00

<p>
在Linux下搞软件开发的朋友，几乎没有不知道strings命令的。我们先用man strings来看看：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_391191">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">strings - print the strings of printable characters </code><code class="bash keyword">in</code> <code class="bash plain">files.</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
意思是，打印文件中可打印的字符。我来补充一下吧，这个文件可以是文本文件（test.c）, 可执行文件(test), 动态链接库(test.o), 静态链接库(test.a)</p>
<p>
脱离代码地长篇大论而不去实际验证，不是我的风格。还是搞点代码下菜吧（代码存在test.c中）：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_806223">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
<div class="line number15 index14 alt2">
15</div>
<div class="line number16 index15 alt1">
16</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp preprocessor">#include <stdio.h> </code>
</div>
<div class="line number2 index1 alt1">
<code class="cpp spaces"> </code>
</div>
<div class="line number3 index2 alt2">
<code class="cpp color1 bold">int</code> <code class="cpp plain">add(</code><code class="cpp color1 bold">int</code> <code class="cpp plain">x, </code><code class="cpp color1 bold">int</code> <code class="cpp plain">y) </code>
</div>
<div class="line number4 index3 alt1">
<code class="cpp plain">{ </code>
</div>
<div class="line number5 index4 alt2">
<code class="cpp spaces">    </code><code class="cpp keyword bold">return</code> <code class="cpp plain">x + y; </code>
</div>
<div class="line number6 index5 alt1">
<code class="cpp plain">} </code>
</div>
<div class="line number7 index6 alt2">
<code class="cpp spaces"> </code>
</div>
<div class="line number8 index7 alt1">
<code class="cpp color1 bold">int</code> <code class="cpp plain">main() </code>
</div>
<div class="line number9 index8 alt2">
<code class="cpp plain">{ </code>
</div>
<div class="line number10 index9 alt1">
<code class="cpp spaces">    </code><code class="cpp color1 bold">int</code> <code class="cpp plain">a = 1; </code>
</div>
<div class="line number11 index10 alt2">
<code class="cpp spaces">    </code><code class="cpp color1 bold">int</code> <code class="cpp plain">b = 2; </code>
</div>
<div class="line number12 index11 alt1">
<code class="cpp spaces">    </code><code class="cpp color1 bold">int</code> <code class="cpp plain">c = add(a, b); </code>
</div>
<div class="line number13 index12 alt2">
<code class="cpp spaces">    </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"oh, my dear, c is %d\n"</code><code class="cpp plain">, c); </code>
</div>
<div class="line number14 index13 alt1">
<code class="cpp spaces"> </code>
</div>
<div class="line number15 index14 alt2">
<code class="cpp spaces">    </code><code class="cpp keyword bold">return</code> <code class="cpp plain">0; </code>
</div>
<div class="line number16 index15 alt1">
<code class="cpp plain">} </code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
我们来看看strings test.c的结果：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_223474">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp plain">$ strings test.c </code>
</div>
<div class="line number2 index1 alt1">
<code class="cpp preprocessor">#include <stdio.h> </code>
</div>
<div class="line number3 index2 alt2">
<code class="cpp color1 bold">int</code> <code class="cpp plain">add(</code><code class="cpp color1 bold">int</code> <code class="cpp plain">x, </code><code class="cpp color1 bold">int</code> <code class="cpp plain">y) </code>
</div>
<div class="line number4 index3 alt1">
<code class="cpp spaces">  </code><code class="cpp keyword bold">return</code> <code class="cpp plain">x + y; </code>
</div>
<div class="line number5 index4 alt2">
<code class="cpp color1 bold">int</code> <code class="cpp plain">main() </code>
</div>
<div class="line number6 index5 alt1">
<code class="cpp spaces">  </code><code class="cpp color1 bold">int</code> <code class="cpp plain">a = 1; </code>
</div>
<div class="line number7 index6 alt2">
<code class="cpp spaces">  </code><code class="cpp color1 bold">int</code> <code class="cpp plain">b = 2; </code>
</div>
<div class="line number8 index7 alt1">
<code class="cpp spaces">  </code><code class="cpp color1 bold">int</code> <code class="cpp plain">c = add(a, b); </code>
</div>
<div class="line number9 index8 alt2">
<code class="cpp spaces">  </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"oh, my dear, c is %d\n"</code><code class="cpp plain">, c); </code>
</div>
<div class="line number10 index9 alt1">
<code class="cpp spaces">  </code><code class="cpp keyword bold">return</code> <code class="cpp plain">0; </code>
</div>
<div class="line number11 index10 alt2">
<code class="cpp plain">$</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
可以看到，确实打印出了test.c中的很多字符。</p>
<p>
下面，我们对可执行文件用strings试试，如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_528932">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">$ gcc </code><code class="bash functions">test</code><code class="bash plain">.c </code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">$ strings a.out </code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">/lib/ld-linux</code><code class="bash plain">.so.2 </code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">=$TsU </code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">__gmon_start__ </code>
</div>
<div class="line number6 index5 alt1">
<code class="bash plain">libc.so.6 </code>
</div>
<div class="line number7 index6 alt2">
<code class="bash plain">_IO_stdin_used </code>
</div>
<div class="line number8 index7 alt1">
<code class="bash functions">printf</code>
</div>
<div class="line number9 index8 alt2">
<code class="bash plain">__libc_start_main </code>
</div>
<div class="line number10 index9 alt1">
<code class="bash plain">GLIBC_2.0 </code>
</div>
<div class="line number11 index10 alt2">
<code class="bash plain">PTRh </code>
</div>
<div class="line number12 index11 alt1">
<code class="bash plain">[^_] </code>
</div>
<div class="line number13 index12 alt2">
<code class="bash plain">oh, my dear, c is %d </code>
</div>
<div class="line number14 index13 alt1">
<code class="bash plain">$ </code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
可以看到，打印出了a.out中很多字符。</p>
<p>
实际上，如果有目标文件、静态库或动态库，，也是可以用strings命令进行打印操作的。我们来看看：</p>
<p>
xxx.h文件：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_119147">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp keyword bold">void</code> <code class="cpp plain">print();</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
xxx.c文件：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_462917">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp preprocessor">#include <stdio.h> </code>
</div>
<div class="line number2 index1 alt1">
<code class="cpp preprocessor">#include "xxx.h" </code>
</div>
<div class="line number3 index2 alt2">
<code class="cpp spaces"> </code>
</div>
<div class="line number4 index3 alt1">
<code class="cpp keyword bold">void</code> <code class="cpp plain">print() </code>
</div>
<div class="line number5 index4 alt2">
<code class="cpp plain">{ </code>
</div>
<div class="line number6 index5 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"rainy days\n"</code><code class="cpp plain">); </code>
</div>
<div class="line number7 index6 alt2">
<code class="cpp plain">} </code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
然后，我们来看看怎么制作静态、动态库吧（在后续博文中会继续详细介绍）：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_788453">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
<div class="line number15 index14 alt2">
15</div>
<div class="line number16 index15 alt1">
16</div>
<div class="line number17 index16 alt2">
17</div>
<div class="line number18 index17 alt1">
18</div>
<div class="line number19 index18 alt2">
19</div>
<div class="line number20 index19 alt1">
20</div>
<div class="line number21 index20 alt2">
21</div>
<div class="line number22 index21 alt1">
22</div>
<div class="line number23 index22 alt2">
23</div>
<div class="line number24 index23 alt1">
24</div>
<div class="line number25 index24 alt2">
25</div>
<div class="line number26 index25 alt1">
26</div>
<div class="line number27 index26 alt2">
27</div>
<div class="line number28 index27 alt1">
28</div>
<div class="line number29 index28 alt2">
29</div>
<div class="line number30 index29 alt1">
30</div>
<div class="line number31 index30 alt2">
31</div>
<div class="line number32 index31 alt1">
32</div>
<div class="line number33 index32 alt2">
33</div>
<div class="line number34 index33 alt1">
34</div>
<div class="line number35 index34 alt2">
35</div>
<div class="line number36 index35 alt1">
36</div>
<div class="line number37 index36 alt2">
37</div>
<div class="line number38 index37 alt1">
38</div>
<div class="line number39 index38 alt2">
39</div>
<div class="line number40 index39 alt1">
40</div>
<div class="line number41 index40 alt2">
41</div>
<div class="line number42 index41 alt1">
42</div>
<div class="line number43 index42 alt2">
43</div>
<div class="line number44 index43 alt1">
44</div>
<div class="line number45 index44 alt2">
45</div>
<div class="line number46 index45 alt1">
46</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">$ </code><code class="bash functions">ls</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">xxx.c xxx.h </code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">$ gcc -c xxx.c </code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">$ ar rcs libxxx.a xxx.o </code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">$ gcc -shared -fPIC -o libxxx.so xxx.o </code>
</div>
<div class="line number6 index5 alt1">
<code class="bash plain">$ </code><code class="bash functions">ls</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash plain">libxxx.a libxxx.so xxx.c xxx.h xxx.o </code>
</div>
<div class="line number8 index7 alt1">
<code class="bash plain">$ strings xxx.o </code>
</div>
<div class="line number9 index8 alt2">
<code class="bash plain">rainy days </code>
</div>
<div class="line number10 index9 alt1">
<code class="bash plain">$ strings libxxx.a </code>
</div>
<div class="line number11 index10 alt2">
<code class="bash plain">!<arch> </code>
</div>
<div class="line number12 index11 alt1">
<code class="bash plain">/        1437887339 0   0   0    14    ` </code>
</div>
<div class="line number13 index12 alt2">
<code class="bash plain">Rprint </code>
</div>
<div class="line number14 index13 alt1">
<code class="bash plain">xxx.o/     1437887333 501 502 100664 848    ` </code>
</div>
<div class="line number15 index14 alt2">
<code class="bash plain">rainy days </code>
</div>
<div class="line number16 index15 alt1">
<code class="bash plain">GCC: (GNU) 4.4.4 20100726 (Red Hat 4.4.4-13) </code>
</div>
<div class="line number17 index16 alt2">
<code class="bash plain">.symtab </code>
</div>
<div class="line number18 index17 alt1">
<code class="bash plain">.strtab </code>
</div>
<div class="line number19 index18 alt2">
<code class="bash plain">.shstrtab </code>
</div>
<div class="line number20 index19 alt1">
<code class="bash plain">.rel.text </code>
</div>
<div class="line number21 index20 alt2">
<code class="bash plain">.data </code>
</div>
<div class="line number22 index21 alt1">
<code class="bash plain">.bss </code>
</div>
<div class="line number23 index22 alt2">
<code class="bash plain">.rodata </code>
</div>
<div class="line number24 index23 alt1">
<code class="bash plain">.comment </code>
</div>
<div class="line number25 index24 alt2">
<code class="bash plain">.note.GNU-stack </code>
</div>
<div class="line number26 index25 alt1">
<code class="bash plain">xxx.c </code>
</div>
<div class="line number27 index26 alt2">
<code class="bash plain">print </code>
</div>
<div class="line number28 index27 alt1">
<code class="bash plain">puts </code>
</div>
<div class="line number29 index28 alt2">
<code class="bash plain">$ </code>
</div>
<div class="line number30 index29 alt1">
<code class="bash plain">$ </code>
</div>
<div class="line number31 index30 alt2">
<code class="bash plain">$ strings libxxx.so </code>
</div>
<div class="line number32 index31 alt1">
<code class="bash plain">__gmon_start__ </code>
</div>
<div class="line number33 index32 alt2">
<code class="bash plain">_init </code>
</div>
<div class="line number34 index33 alt1">
<code class="bash plain">_fini </code>
</div>
<div class="line number35 index34 alt2">
<code class="bash plain">__cxa_finalize </code>
</div>
<div class="line number36 index35 alt1">
<code class="bash plain">_Jv_RegisterClasses </code>
</div>
<div class="line number37 index36 alt2">
<code class="bash plain">print </code>
</div>
<div class="line number38 index37 alt1">
<code class="bash plain">puts </code>
</div>
<div class="line number39 index38 alt2">
<code class="bash plain">libc.so.6 </code>
</div>
<div class="line number40 index39 alt1">
<code class="bash plain">_edata </code>
</div>
<div class="line number41 index40 alt2">
<code class="bash plain">__bss_start </code>
</div>
<div class="line number42 index41 alt1">
<code class="bash plain">_end </code>
</div>
<div class="line number43 index42 alt2">
<code class="bash plain">GLIBC_2.1.3 </code>
</div>
<div class="line number44 index43 alt1">
<code class="bash plain">GLIBC_2.0 </code>
</div>
<div class="line number45 index44 alt2">
<code class="bash plain">rainy days </code>
</div>
<div class="line number46 index45 alt1">
<code class="bash plain">$ </code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
看到了吧。</p>
<p>
strings命令很简单，看起来好像没什么，但实际有很多用途。下面，我来举一个例子。在大型的软件开发中，假设有100个.c/.cpp文件，这个.cpp文件最终生成10个.so库，那么怎样才能快速知道某个.c/.cpp文件编译到那个.so库中去了呢？当然，你可能要说，看makefile不就知道了。对，看makefile肯定可以，但如下方法更好，直接用命令：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_109645">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">strings -f </code><code class="bash string">"*.so"</code> <code class="bash plain">| </code><code class="bash functions">grep</code> <code class="bash string">"xxxxxx"</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
如果还不明白，那就就以上面的小程序为例为说明，不过，此处我们考虑所有的文件，如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_945248">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">$ strings -f * | </code><code class="bash functions">grep</code> <code class="bash string">"my dear"</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">a.out: oh, my dear, c is %d </code>
</div>
<div class="line number3 index2 alt2">
<code class="bash functions">test</code><code class="bash plain">.c:   </code><code class="bash functions">printf</code><code class="bash plain">(</code><code class="bash string">"oh, my dear, c is %d\n"</code><code class="bash plain">, c); </code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">$</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
可以看到，源文件test.c和可执行文件中皆有"my dear"串，一下子就找到了对应的文件，清楚了吧。如果某.c/.cpp文件编译进了.so库，那么，strings -f * | grep "my dear"必定可以找到对应的.so文件，其中"my dear"为该.c/.cpp文件中的某个日志串（比如以printf为打印）。</p>
<p>
strings的作用先介绍到此，算是抛砖引玉地熟悉一下strings吧。</p>
<p>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。</p>
<p>
原文链接：http://blog.csdn.net/stpeace/article/details/46641069</p>

頁: [1]

琼殿技术论坛's Archiver

详解linux中的strings命令简介