Linux-----sed案例练习

1.数据准备

准备数据如下：

bash 复制代码

[root@openEuler ~]# cat openlab.txt 
My name is jock.
I teach linux.
I like play computer game.
My qq is 24523452
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com

2.题目

2.1、输出文件第2，3行的内容：

bash 复制代码

[root@openEuler ~]# sed -n '2,3p' openlab.txt 
I teach linux.
I like play computer game.

2.2、过滤出含有linux的字符串行：

bash 复制代码

[root@openEuler ~]# sed -n '/linux/p' openlab.txt 
I teach linux.

2.3、删除含有game的行：

bash 复制代码

[root@openEuler ~]# sed '/game/d' openlab.txt 
My name is jock.
I teach linux.
My qq is 24523452
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com

2.4、删除第5行到结尾：

bash 复制代码

[root@openEuler ~]# sed '5,$d' openlab.txt 
My name is jock.
I teach linux.
I like play computer game.
My qq is 24523452

2.5、将文件中的My全部替换为His：

bash 复制代码

[root@openEuler ~]# sed 's/My/His/g' openlab.txt 
His name is jock.
I teach linux.
I like play computer game.
His qq is 24523452
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com

2.6、替换所有My为His，同时换掉QQ号为88888888：

bash 复制代码

[root@openEuler ~]# sed -e 's/My/His/g' -e 's/24523452/88888888/g' openlab.txt 
His name is jock.
I teach linux.
I like play computer game.
His qq is 88888888
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com
His website is http://www.xianoupeng.com

2.7、在文件第二行追加内容（ a 字符功能），写入到文件（-i）：

bash 复制代码

[root@openEuler ~]# sed -i '2a I like liunx' openlab.txt 
[root@openEuler ~]# cat openlab.txt 
My name is jock.
I teach linux.
I like liunx
I like play computer game.
My qq is 24523452
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com

2.8、添加多行信息，用换行符"\n"：

bash 复制代码

[root@openEuler ~]# sed -i '3a I like liunx very much!\nand you?' openlab.txt 
[root@openEuler ~]# cat openlab.txt 
My name is jock.
I teach linux.
I like liunx
I like liunx very much!
and you?
I like play computer game.
My qq is 24523452
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com

2.9、在每一行下面插入新内容：

bash 复制代码

[root@openEuler ~]# sed 'a ----------------------------------------' openlab.txt 
My name is jock.
----------------------------------------
I teach linux.
----------------------------------------
I like liunx
----------------------------------------
I like liunx very much!
----------------------------------------
and you?
----------------------------------------
I like play computer game.
----------------------------------------
My qq is 24523452
----------------------------------------
My website is http://www.xianoupeng.com
----------------------------------------
My website is http://www.xianoupeng.com
----------------------------------------
My website is http://www.xianoupeng.com
----------------------------------------
My website is http://www.xianoupeng.com
----------------------------------------
My website is http://www.xianoupeng.com
----------------------------------------
My website is http://www.xianoupeng.com
----------------------------------------

2.10、在第二行上面插入内容：

bash 复制代码

[root@openEuler ~]# sed -i '2i I am a boy.' openlab.txt 
[root@openEuler ~]# cat openlab.txt 
My name is jock.
I am a boy.
I teach linux.
I like liunx
I like liunx very much!
and you?
I like play computer game.
My qq is 24523452
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com
My website is http://www.xianoupeng.com

注意：sed对文件进行操作处理时，改变的只是内存中的文件数据，源文件的数据不会发生改变，如果想对文件内的内容进行处理则需要加上 -i 这个选项。

3.补充-----sed的工作流程

如图所示：

如上面的图片一样，sed工作时会一行一行的读取文件内容，每次读取一行放入sed模式空间，然后与匹配模式相匹配，不管匹配成功还是失败，都会输出到屏幕上。失败则是直接将原内容输出，成功则是输出编辑处理过的数据。默认的输出可以取消（使用-n 选项）。