Linux基础学习总结（五）

1、显示当前系统上root、fedora或user1用户的默认shell；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">grep </span><span class="pun">-</span><span class="pln">E </span><span class="str">'^(root|fedora|user1)\&gt;'</span><span class="pln"> </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln">passwd </span><span class="pun">|</span><span class="pln"> awk </span><span class="pun">-</span><span class="pln">F </span><span class="str">':'</span><span class="pln"> </span><span class="str">'{print $7}'</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">grep -E '^(root|fedora|user1)\>' /etc/passwd | awk -F ':' '{print $7}'</code></li></ol>

2、找出/etc/rc.d/init.d/functions文件中某单词后面跟一组小括号的行，形如：hello()；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">grep </span><span class="pun">-</span><span class="pln">E </span><span class="str">'[_[:alnum:]]+\(\)'</span><span class="pln"> </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln">rc</span><span class="pun">.</span><span class="pln">d</span><span class="pun">/</span><span class="pln">init</span><span class="pun">.</span><span class="pln">d</span><span class="pun">/</span><span class="pln">functions</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">grep -E '[_[:alnum:]]+' /etc/rc.d/init.d/functions</code></li></ol>

3、使用echo命令输出一个路径，使用grep取出其基名；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">echo </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln">passwd </span><span class="pun">|</span><span class="pln"> grep </span><span class="pun">-</span><span class="pln">E </span><span class="pun">-</span><span class="pln">o </span><span class="str">"[^/]+/?$"</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">echo /etc/passwd | grep -E -o "[^/]+/?$"</code></li></ol>

扩展：取出其路径名；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">echo </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln">passwd </span><span class="pun">|</span><span class="pln"> grep </span><span class="pun">-</span><span class="pln">E </span><span class="pun">-</span><span class="pln">o </span><span class="str">"/[[:alpha:]]*/"</span></code></li></ol>

4、找出ifconfig命令结果中的1-255之间数字；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">ifconfig </span><span class="pun">|</span><span class="pln"> grep </span><span class="pun">-</span><span class="pln">E </span><span class="pun">-</span><span class="pln">o </span><span class="str">"\&lt;([1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\&gt;"</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">ifconfig | grep -E -o "\<([1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\>"</code></li></ol>

5、写一个模式，能匹配出合理的IP地址；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">ifconfig </span><span class="pun">|</span><span class="pln"> grep </span><span class="pun">-</span><span class="pln">E </span><span class="pun">-</span><span class="pln">o </span><span class="str">'([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])\.([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])\.([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])\.([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])'</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">ifconfig | grep -E -o '([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])\.([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])\.([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])\.([0-9]{1,2}|1[0-9][0-9]|2[0-5][0-5])'</code></li></ol>

6、写一个模式，能匹配出所有的邮件地址；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="str">"\&lt;[a-zA-Z0-9_-]*@[A-Za-z0-9_-]*\.[a-zA-Z_-]*$\&gt;"</span></code></li></ol>

1	<ol class="linenums"><li class="L0"><code class="language-sh"><span class="str">"\<[a-zA-Z0-9_-]@[A-Za-z0-9_-]\.[a-zA-Z_-]*$\>"</span></code></li></ol>

7、查找/var目录下属主为root，且属组为mail的所有文件和目录；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">var </span><span class="pun">-</span><span class="pln">user root </span><span class="pun">-</span><span class="pln">a </span><span class="pun">-</span><span class="pln">group mail</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">find /var -user root -a -group mail</code></li></ol>

8、查找当前系统上没有属主或属组的文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln"> </span><span class="pun">-</span><span class="pln">nouser </span><span class="pun">-</span><span class="pln">o </span><span class="pun">-</span><span class="pln">nogroup </span><span class="pun">-</span><span class="pln">ls</span></code></li></ol>

查找当前系统上没有属主或属组，且最近3天内曾被访问过的文件或目录；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln"> </span><span class="pun">-</span><span class="pln">nouser </span><span class="pun">-</span><span class="pln">a </span><span class="pun">-</span><span class="pln">nogroup </span><span class="pun">-</span><span class="pln">a </span><span class="pun">-</span><span class="pln">atime </span><span class="pun">+</span><span class="lit">3</span><span class="pln"> </span><span class="pun">-</span><span class="pln">ls</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">find / -nouser -a -nogroup -a -atime +3 -ls</code></li></ol>

9、查找/etc目录下所有用户都有写权限的文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">etc </span><span class="pun">-</span><span class="pln">perm </span><span class="lit">222</span><span class="pln"> </span><span class="pun">-</span><span class="pln">type f </span><span class="pun">-</span><span class="pln">exec ls </span><span class="pun">-</span><span class="pln">lh </span><span class="pun">{}</span><span class="pln"> \;</span></code></li></ol>

10、查找/etc目录下大于1M，且目录类型为普通文件的所有文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">etc </span><span class="pun">-</span><span class="pln">size </span><span class="pun">+</span><span class="lit">1M</span><span class="pln"> </span><span class="pun">-</span><span class="pln">type f </span><span class="pun">-</span><span class="pln">exec ls </span><span class="pun">-</span><span class="pln">lh </span><span class="pun">{}</span><span class="pln"> \;</span></code></li><li class="L1"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">etc </span><span class="pun">-</span><span class="pln">size </span><span class="pun">+</span><span class="lit">1M</span><span class="pln"> </span><span class="pun">-</span><span class="pln">type f </span><span class="pun">|</span><span class="pln">xargs ls </span><span class="pun">-</span><span class="pln">lh</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">find /etc -size +1M -type f -exec ls -lh {} \;</code></li><li class="L1"><code class="language-sh">find /etc -size +1M -type f |xargs ls -lh</code></li></ol>

11、查找/etc/init.d/目录下，所有用户都有执行权限，且其它用户有写权限的文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln">init</span><span class="pun">.</span><span class="pln">d</span><span class="pun">/</span><span class="pln"> </span><span class="pun">-</span><span class="pln">perm </span><span class="pun">/</span><span class="lit">113</span><span class="pln"> </span><span class="pun">-</span><span class="pln">type f </span><span class="pun">-</span><span class="pln">ls</span></code></li></ol>

12、查找/usr目录下不属于root、bin或hadoop的文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">usr </span><span class="pun">-</span><span class="pln">not \( </span><span class="pun">-</span><span class="pln">user root </span><span class="pun">-</span><span class="pln">o </span><span class="pun">-</span><span class="pln">user bin </span><span class="pun">-</span><span class="pln">o </span><span class="pun">-</span><span class="pln">user hadoop \) </span><span class="pun">-</span><span class="pln">exec ls </span><span class="pun">-</span><span class="pln">ld </span><span class="pun">{}</span><span class="pln"> \;</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">find /usr -not $ -user root -o -user bin -o -user hadoop $ -exec ls -ld {} \;</code></li></ol>

13、查找/etc/目录下至少有一类用户没有写权限的文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln"> </span><span class="pun">-</span><span class="pln">not </span><span class="pun">-</span><span class="pln">perm </span><span class="pun">/</span><span class="lit">222</span><span class="pln"> </span><span class="pun">-</span><span class="pln">type f </span><span class="pun">-</span><span class="pln">exec ls </span><span class="pun">-</span><span class="pln">lh </span><span class="pun">{}</span><span class="pln"> \;</span></code></li></ol>

14、查找/etc目录下最近一周内其内容被修改过，且不属于root或hadoop的文件；

<ol class="linenums"><li class="L0"><code class="language-sh"><span class="pln">find </span><span class="pun">/</span><span class="pln">etc</span><span class="pun">/</span><span class="pln"> </span><span class="pun">-</span><span class="pln">mtime </span><span class="pun">-</span><span class="lit">7</span><span class="pln"> </span><span class="pun">-</span><span class="pln">a </span><span class="pun">-</span><span class="pln">not \( </span><span class="pun">-</span><span class="pln">user root </span><span class="pun">-</span><span class="pln">o </span><span class="pun">-</span><span class="pln">user hadoop \) </span><span class="pun">-</span><span class="pln">exec ls </span><span class="pun">-</span><span class="pln">ldh </span><span class="pun">{}</span><span class="pln"> \;</span></code></li></ol>

<ol class="linenums"><li class="L0"><code class="language-sh">find /etc/ -mtime -7 -a -not $ -user root -o -user hadoop $ -exec ls -ldh {} \;</code></li></ol>

来自为知笔记(Wiz)

原创文章，作者：Leexide，如若转载，请注明出处：http://www.178linux.com/53321