Linux文件系统组成和基本操作

1、文件系统的组成

• 文件和目录构成单根倒树状结构
• 文件系统从根目录开始，表示为一个单独的“/”字符
• 命名区分大小写
• 路径之间以“/”分隔

2、重要目录

• /root：超级用户root的家目录；
• /home/username：普通用户的家目录；
• /usr：安装的软件、共享库等目录；
• /usr/bin：用户命令，存放的路径；
• /usr/sbin：系统管理员命令；
• /usr/local：本地自定义软件安装目录；
• /etc：系统的配置文件；
• /var：系统服务的数据，例如数据库文件、日志文件和网站内容等；
• /tmp：系统临时文件目录；
• /boot：系统启动所需要的文件；
• /dev：包含一些特殊的设备文件，供系统用于访问硬件；
• /proc和/sys：反应当前系统运行状态；

3、文件和目录名

• 文件及目录的名字不能多于255个字符
• 所有字符都要求是有效的，不能使用“/”作为文件名
  • 文件或目录名中不要使用特殊字符
  • 如果文件名中含有特殊字符时应该使用单引号引起来
• 在Linux中命名区分大小写

4、绝对路径和相对路径

• 绝对路径
  • 以根开头的路径
  • 文件位置的全路径
  • 在任何位置都可以引用
• 相对路径
  • 不以斜线开头
  • 当前工作目录的相对位置
  • 在特定的位置才可以引用

5、基本操作

pwd：显示当前工作目录

[erik@localhost ~]$ pwd
/home/erik
[erik@localhost ~]$

cd：改变到一个绝对或相对目录

• cd ..：回退到上一层目录
• cd -：回退到上一次所在的工作目录
• cd/cd ~：改变的哦啊当前用户的主目录
• cd ~username：改变到某个用户的主目录

[erik@localhost ~]$ cd /etc
[erik@localhost etc]$ cd ..
[erik@localhost /]$ cd ~
[erik@localhost ~]$ 

ls：列出当前目录或者指定目录下的内容

• ls -a：包含隐藏文件
• ls -l：显示扩展信息
• ls -R：递归所有目录
• ls -ld：显示目录和符号链接信息

<span class="hljs-string">[erik@localhost</span> <span class="hljs-string">~]$</span> <span class="hljs-string">ls</span>
<span class="hljs-string">Desktop</span>  <span class="hljs-string">Documents</span>  <span class="hljs-string">Downloads</span>  <span class="hljs-string">Music</span>  <span class="hljs-string">Pictures</span>  <span class="hljs-string">Public</span>  <span class="hljs-string">Templates</span>  <span class="hljs-string">Videos</span>
<span class="hljs-string">[erik@localhost</span> <span class="hljs-string">~]$</span> <span class="hljs-string">ls</span> <span class="hljs-string">-a</span>
<span class="hljs-string">.</span>              <span class="hljs-string">.bash_profile</span>  <span class="hljs-string">Desktop</span>    <span class="hljs-string">.ICEauthority</span>  <span class="hljs-string">Pictures</span>
<span class="hljs-string">..</span>             <span class="hljs-string">.bashrc</span>        <span class="hljs-string">Documents</span>  <span class="hljs-string">.local</span>         <span class="hljs-string">Public</span>
<span class="hljs-string">.bash_history</span>  <span class="hljs-string">.cache</span>         <span class="hljs-string">Downloads</span>  <span class="hljs-string">.mozilla</span>       <span class="hljs-string">Templates</span>
<span class="hljs-string">.bash_logout</span>   <span class="hljs-string">.config</span>        <span class="hljs-string">.esd_auth</span>  <span class="hljs-string">Music</span>          <span class="hljs-string">Videos</span>
<span class="hljs-string">[erik@localhost</span> <span class="hljs-string">~]$</span> <span class="hljs-string">ls</span> <span class="hljs-string">-R</span>
<span class="hljs-string">.:</span>
<span class="hljs-string">Desktop</span>  <span class="hljs-string">Documents</span>  <span class="hljs-string">Downloads</span>  <span class="hljs-string">Music</span>  <span class="hljs-string">Pictures</span>  <span class="hljs-string">Public</span>  <span class="hljs-string">Templates</span>  <span class="hljs-string">Videos</span>

<span class="hljs-string">./Desktop:</span>

<span class="hljs-string">./Documents:</span>

<span class="hljs-string">./Downloads:</span>

<span class="hljs-string">./Music:</span>

<span class="hljs-string">./Pictures:</span>

<span class="hljs-string">./Public:</span>

<span class="hljs-string">./Templates:</span>

<span class="hljs-string">./Videos:</span>
<span class="hljs-string">[erik@localhost</span> <span class="hljs-string">~]$</span> <span class="hljs-string">ls</span> <span class="hljs-string">-ld</span>
<span class="hljs-string">drwx------.</span> <span class="hljs-number">14</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">4096</span> <span class="hljs-string">Mar</span> <span class="hljs-number">26</span> <span class="hljs-number">06</span><span class="hljs-string">:23</span> <span class="hljs-string">.</span>
<span class="hljs-string">[erik@localhost</span> <span class="hljs-string">~]$</span> <span class="hljs-string">ll</span>
<span class="hljs-string">total</span> <span class="hljs-string">0</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Desktop</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Documents</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Downloads</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Music</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Pictures</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Public</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Templates</span>
<span class="hljs-string">drwxr-xr-x.</span> <span class="hljs-number">2</span> <span class="hljs-string">erik</span> <span class="hljs-string">erik</span> <span class="hljs-number">6</span> <span class="hljs-string">Mar</span> <span class="hljs-number">23</span> <span class="hljs-number">05</span><span class="hljs-string">:33</span> <span class="hljs-string">Videos</span>
<span class="hljs-string">[erik@localhost</span> <span class="hljs-string">~]$</span> 

touch：创建一个空文件或者更新一个文件的时间戳

• 如果文件不存在，则创建空文件
• 如果文件已存在，则更新文件的时间戳
  • atime（access time）：文件最后一次被访问的时间
  • mtime（modify time）：文件最后一次被修改的时间（文件内容发生变化）
  • ctime（change time）：文件最后一次被改变的时间（文件属性发生变化，例如文件的权限、大小）
  • Birth：文件被创建的时间（红帽没有开启该时间）

cp：拷贝文件和目录

• 格式：cp [option] file destination
• 如果destination是一个目录，可以一次拷贝多个文件到这个目录，cp [option] file1 file2 destination
• destination说明：
  • 如果目标是一个目录，该拷贝把文件放到该目录下
  • 如果目标是一个文件，该拷贝覆盖目标文件
  • 如果目标不存在，该拷贝被重命名
• 拷贝目录使用cp -r

<span class="hljs-selector-attr">[root@localhost erik]</span># <span class="hljs-selector-tag">touch</span> <span class="hljs-selector-tag">test</span><span class="hljs-selector-class">.txt</span>
<span class="hljs-selector-attr">[root@localhost erik]</span># <span class="hljs-selector-tag">ls</span>
<span class="hljs-selector-tag">Desktop</span>    <span class="hljs-selector-tag">Downloads</span>  <span class="hljs-selector-tag">Pictures</span>  <span class="hljs-selector-tag">Templates</span>  <span class="hljs-selector-tag">Videos</span>
<span class="hljs-selector-tag">Documents</span>  <span class="hljs-selector-tag">Music</span>      <span class="hljs-selector-tag">Public</span>    <span class="hljs-selector-tag">test</span><span class="hljs-selector-class">.txt</span>
<span class="hljs-selector-attr">[root@localhost erik]</span># <span class="hljs-selector-tag">pwd</span>
/<span class="hljs-selector-tag">home</span>/<span class="hljs-selector-tag">erik</span>
<span class="hljs-selector-attr">[root@localhost erik]</span><span class="hljs-selector-id">#ls</span> /<span class="hljs-selector-tag">opt</span>
<span class="hljs-selector-tag">rh</span> 
<span class="hljs-selector-attr">[root@localhost erik]</span># <span class="hljs-selector-tag">cp</span> <span class="hljs-selector-tag">test</span><span class="hljs-selector-class">.txt</span> /<span class="hljs-selector-tag">opt</span>/
<span class="hljs-selector-attr">[root@localhost erik]</span># <span class="hljs-selector-tag">ls</span> /<span class="hljs-selector-tag">opt</span>
<span class="hljs-selector-tag">rh</span>  <span class="hljs-selector-tag">test</span><span class="hljs-selector-class">.txt</span>
<span class="hljs-selector-attr">[root@localhost erik]</span># 

mv：移动或者重命名文件和目录

• mv的源文件和目标文件在同一个目录就是重命名，不在同一个目录就是移动
• 格式：mv [option] file destination
• 如果目标是一个目录可以同时移动多个文件，mv [option] file1 file2 destination

[root@localhost erik]<span class="hljs-comment"># touch test1.txt</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> erik]# ls</span>
<span class="hljs-comment">Desktop    Downloads  Pictures  Templates  test.txt</span>
<span class="hljs-comment">Documents  Music      Public    test1.txt  Videos</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> erik]# mv test1.txt /opt</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> erik]# ls /opt/</span>
<span class="hljs-comment">rh  test1.txt  test.txt</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> erik]# </span>

rm：删除文件

• 格式：rm [option] <file…
• rm -i file：交互式删除，默认存在
• rm -r directory：递归删除
• rm -f file：强制删除

[root@localhost opt]<span class="hljs-comment"># rm test.txt </span>
<span class="hljs-comment">rm: remove regular empty file ‘test.txt’? yes</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> opt]# ls</span>
<span class="hljs-comment">rh  test1.txt</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> opt]# </span>

<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> /]# rm /opt/test1.txt </span>
<span class="hljs-comment">rm: remove regular empty file ‘/opt/test1.txt’? yes</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> /]# ls /opt</span>
<span class="hljs-comment">rh</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> /]# </span>

mkdir：创建空目录

• mkdir -p：递归创建目录
• rmdir：删除空目录

[root@localhost /]<span class="hljs-comment"># mkdir /opt/test1</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> /]# ls /opt/</span>
<span class="hljs-comment">rh  test1</span>
<span class="hljs-comment">[root<span class="hljs-doctag">@localhost</span> /]# </span>

file：查看文件类型（Linux中没有文件后缀名）

[root@localhost <span class="hljs-regexp">/]# file /opt/test1/</span>
<span class="hljs-regexp">/opt/test1/</span>: directory
[root@localhost /]<span class="hljs-comment"># </span>