sed 替换命令使用

Posted 2021-09-03 风风羊

输入文件不会被修改，sed 只在模式空间中执行替换命令，然后输出模式空间的
内容。
文本文件 employee.txt

101,John Doe,CEO
102,Jason Smith,IT Manager
103,Raj Reddy,Sysadmin
104,Anand Ram,Developer
105,Jane Miller,Sales Manager

1.用 Director 替换所有行中的 Manager

替换命令用到参数s 注意代码格式

[root@localhost /]# sed \'s/Manager/Director/\' employee.txt
101,John Doe,CEO
102,Jason Smith,IT Director
103,Raj Reddy,Sysadmin
104,Anand Ram,Developer
105,Jane Miller,Sales Director

 

2.只把包含 Sales 的行中的 Manager 替换为 Director

[root@localhost /]# sed \'/Sales/s/Manager/Director/\' employee.txt
101,John Doe,CEO
102,Jason Smith,IT Manager
103,Raj Reddy,Sysadmin
104,Anand Ram,Developer
105,Jane Miller,Sales Director

 

3.全局标志 g

用大写 A 替换第一次出现的小写字母 a

[root@localhost /]# sed \'s/a/A/\' employee.txt
101,John Doe,CEO
102,JAson Smith,IT Manager
103,RAj Reddy,Sysadmin
104,AnAnd Ram,Developer
105,JAne Miller,Sales Manager

 

把所有小写字母 a 替换为大写字母 A

[root@localhost /]# sed \'s/a/A/g\' employee.txt
101,John Doe,CEO
102,JAson Smith,IT MAnAger
103,RAj Reddy,SysAdmin
104,AnAnd RAm,Developer
105,JAne Miller,SAles MAnAger

 

4.数字标志

把第二次出现的小写字母 a 替换为大写字母 A

[root@localhost /]# sed \'s/a/A/2\' employee.txt
101,John Doe,CEO
102,Jason Smith,IT MAnager
103,Raj Reddy,SysAdmin
104,Anand RAm,Developer
105,Jane Miller,SAles Manager

建立一下文件

vi substitute-locate.txt
locate command is used to locate files
locate command uses database to locate files
locate command can also use regex for searching

 

用刚才建立的文件，把每行中第二次出现的 locate 替换为 find

[root@localhost /]# sed \'s/locate/find/2\' substitute-locate.txt
locate command is used to find files
locate command uses database to find files
locate command can also use regex for searching

 

5.打印标志 p

只打印替换后的行

[root@localhost /]# sed -n \'s/John/johnny/p\' employee.txt
101,johnny Doe,CEO

 

把每行中第二次出现的 locate 替换为 find 并打印出来

[root@localhost /]# sed -n \'s/locate/find/2p\' substitute-locate.txt
locate command is used to find files
locate command uses database to find files

 

6.写标志w

标志 w 代表 write，当替换操作执行成功后，它把替换后的结果保存的文件。
把每行出现的 John 替换为 Johnny，只把替换后的内容写到 output.txt 中

[root@localhost /]# sed -n \'s/John/Johnny/w output.txt\' employee.txt
[root@localhost /]# cat output.txt
101,Johnny Doe,CEO

 

把每行第二次出现的 locate 替换为 find，把替换的结果保存到文件中，同时显示输入文件所有内容

[root@localhost /]# sed \'s/locate/find/2w output.txt\' substitute-locate.txt
locate command is used to find files
locate command uses database to find files
locate command can also use regex for searching
[root@localhost /]# cat output.txt
locate command is used to find files
locate command uses database to find files

 

7.忽略大小写标志 i

把 john 或 John 替换为 Johnny,但是文件中的John中的J是大写，所以用i参数忽略大小写

[root@localhost /]# sed \'s/john/Johnny/i\' employee.txt
101,Johnny Doe,CEO
102,Jason Smith,IT Manager
103,Raj Reddy,Sysadmin
104,Anand Ram,Developer
105,Jane Miller,Sales Manager

 

8.执行命令标志 e

如下图所示，e参数就是执行的作用 文本文件ls -l /etc/passwd e参数则是执行这条命令

[root@localhost /]# vi /files.txt
[root@localhost /]# cat /files.txt
/etc/passwd
/etc/group
[root@localhost /]# sed \'s/^/ls -l/\' files.txt
ls -l/etc/passwd
ls -l/etc/group
[root@localhost /]# sed \'s/^/ls -l /e\' files.txt
-rw-r--r--. 1 root root 1766 10月 24 15:15 /etc/passwd
-rw-r--r--. 1 root root 920 10月 24 15:15 /etc/group

 

原文链接：https://blog.csdn.net/weixin_43150761/article/details/83152456