Linux centos7 sed工具介绍

Posted 2020-11-01 davery

一、sed上

grep工具功能只能实现查找，不能把查找的内容替换。

sed本身是一个管道命令，主要是以行为单位进行处理，可以将数据行进行查找、删除、替换字符或字符串、调换字符串位置、直接修改文件内容等特定工作，针对文档的行来操作，例如.txt。

 

[[email protected] ~]# mkdir sed
[[email protected] ~]# cd sed
[[email protected] sed]# cp ../grep/passwd 0.txt
[[email protected] sed]#
[[email protected] sed]# pwd
/root/sed
[[email protected] sed]# ls
0.txt
[[email protected] sed]#

查找：sed -n ‘/关键词/‘p  文件名 

[[email protected] sed]# sed -n ‘2‘p 0.txt  显示第二行

[[email protected] sed]# sed ‘15,$‘p 0.txt  显示15行到最后一行

[[email protected] sed]# sed -n ‘1,$‘p 0.txt 显示全部

[[email protected] sed]#sed -n ‘/^1/‘p 0.txt  

[[email protected] sed]#sed -n ‘/in$/‘p 0.txt

[[email protected] sed]#sed -n ‘/r..o/‘p 0.txt

[[email protected] sed]#sed -n ‘/oo*/‘p 0.txt

[[email protected] sed]#sed -n ‘/oo*/‘Ip 0.txt   加入大写I，不区分大小写

删除：sed -n  ‘关键词‘p 文件名   ，仅仅是在屏幕中列出未删除的行，其实原文件并没有被删除。

[[email protected] sed]#sed -n ‘5‘p 0.txt

[[email protected] sed]#sed -n ‘1,5‘p 0.txt

[[email protected] sed]#sed -n ‘1,$‘p 0.txt

[[email protected] sed]#sed -n ‘/root/‘p 0.txt

[[email protected] sed]#sed -n ‘/^1/‘p 0.txt

[[email protected] sed]#sed -n ‘/in$/‘p 0.txt

[[email protected] sed]#sed -n ‘/r..o/‘p 0.txt

[[email protected] sed]#sed -n ‘/oo*/‘p 0.txt

替换： s表示替换动作，g表示本行全局替换，除了用/作为分割符，也可用特殊字符#、@

[[email protected] sed]# sed ‘1,2s/ot/to/g‘ 0.txt  第一二行，ot替换成to

[[email protected] sed]# sed -r ‘1,2s/ot+/to/g‘ 0.txt

[[email protected] sed]# sed ‘s#ot#to#g‘ 0.txt  

[[email protected] sed]# sed ‘[email protected]@[email protected]‘ 0.txt  

[[email protected] sed]# sed ‘s/[0-9]//g‘ 0.txt     

 

[[email protected] sed]# sed ‘s/[a-zA-Z]//g‘ 0.txt

调换两个字符位置

[[email protected] sed]# sed ‘s/\(root\)\(.*\)\(bash\)/\3\2\1/‘ 0.txt  

[[email protected] sed]# sed -r ‘s/(root)(.*)(bash)/\3\2\1/‘ 0.txt    加入-r表达式更清晰

bash:x:0:0:root:/root:/bin/root

[[email protected] sed]# sed -r ‘s/(uaer)(.*)(bash)/\3\2\1/‘ 0.txt

bash1:x:1001:1004::/home/uaer1:/bin/uaer

[[email protected] sed]# sed ‘s/^.*$/123&/‘ 0.txt      最前边加123    

123root:x:0:0:root:/root:/bin/bash
123bin:x:1:1:bin:/bin:/sbin/NOLOGIN

直接修改文件内容

[[email protected] sed]# sed -i ‘s/root/toor/g‘ 0.txt
[[email protected] sed]# cat 0.txt
toor:x:0:0:toor:/toor:/bin/bash

 

例子

[[email protected] sed]# sed ‘/root/‘p 0.txt   会显示所有行
root:x:0:0:root:/root:/bin/bash
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/NOLOGIN
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
[[email protected] sed]# sed -n ‘/root/‘p 0.txt  只把关键词目标行显示出来
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

[[email protected] sed]# sed -nr ‘/root|bus/‘p 0.txt   加入r

root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

[[email protected] sed]# sed -nr ‘/o+t/‘p 0.txt
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

dbus:x:81:81:System message bus:/:/sbin/nologin

[[email protected] sed]# sed -nr ‘/o{2}/‘p 0.txt
root:x:0:0:root:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin