三剑客之sed
注意sed和awk使用单引号，双引号有特殊解释
sed是stream editor（字符交流编辑器）的缩写，简称流编辑器。
sed是操作、过滤和转换文本内容的强大的工具。
常用功能包括结合正则表达式对文件实现快速增删改查，其中查询的功能中最常用的两大功能是过滤（过滤指定字符串）、取行（取出指定行）。
语法:
sed [选项] [sed内置命令字符] [输入文件]
选项:
| 参数选项 | 解释 |
|---|---|
| -n | 取消默认sed的输出，常与sed内置命令p一起用 |
| -i | 直接将修改结果写入文件，不用-i,sed修改的是内存数据 |
| -e | 多次编辑，不需要管道符 |
| -r | 支持正则扩展 |
sed的 内置命令字符 用于对文件进行不同的操作功能，如对文件增删改查
sed常用，内置命令字符：
| sed的内置命令字符 | 解释 |
|---|---|
| a | append，对文本追加，在指定行后面添加一行/多行文本 |
| d | Delete，删除匹配行 |
| i | insert，表示插入文本，在指定行前添加一行、多行文本 |
| p | Print，打印匹配行的内容，通常p与-n一起用 |
| s/正则/替换内容/g | 匹配正则内容，然后替换内容（支持正则），结尾g代表全局匹配 |
sed匹配范围
| 范围 | 解释 |
|---|---|
| 空地址 | 全文处理 |
| 单地址 | 指定文件某一行 |
| /pattern/ | 被模式匹配道的每一行 |
| 范围区间 | 10，20十到二十行，10，+5第十行向下5行，/pattern1/，/pattern2/ |
| 步长 | 12，表示1、3、5、7、9行，22两个步长，表示2、4、6、8、10、偶数行 |
sed案例
准备测试数据
[root@xuexi3 home]# touch cssed.txt
[root@xuexi3 home]# vim cssed.txt
[root@xuexi3 home]# cat -n cssed.txt
1 My name is maitekai.
2 I teach huoying.
3 I like play computer game.
4 My qq is 12357800
5 My website is http://pythonav.cn
[root@xuexi3 home]#
1.输出文件第2，3的内容
[root@xuexi3 home]# sed "2,3p" cssed.txt
My name is maitekai.
I teach huoying.
I teach huoying.
I like play computer game.
I like play computer game.
My qq is 12357800
My website is http://pythonav.cn
[root@xuexi3 home]# sed "2,3p" cssed.txt -n #P与-N一起使用
I teach huoying.
I like play computer game.
2.过滤含有linux的行
[root@xuexi3 home]# sed "/linux/p" cssed.txt -n
I teach linux.
[root@xuexi3 home]#
3删除含有game的行
[root@xuexi3 home]# sed "/game/d" cssed.txt #sed修改的是内存的数据
My name is maitekai.
I teach linux.
My qq is 12357800
My website is http://pythonav.cn
[root@xuexi3 home]# cat cssed.txt #实际文件内容不会修改
My name is maitekai.
I teach linux.
I like play computer game.
My qq is 12357800
My website is http://pythonav.cn
[root@xuexi3 home]# sed "/game/d" cssed.txt -i # -i参数将结果写入文件
[root@xuexi3 home]# cat cssed.txt
My name is maitekai.
I teach linux.
My qq is 12357800
My website is http://pythonav.cn
4 sed删除第五行以后的数据并输出到文件
[root@xuexi3 home]# sed "5,$ d" cssed.txt -i
[root@xuexi3 home]# cat cssed.txt
My name is maitekai.
I teach linux.
My qq is 12357800
My website is http://pythonav.cn
5将文件中的My全部替换为His
[root@xuexi3 home]# sed "s/My/His/g" cssed.txt
His name is maitekai.
I teach linux.
His qq is 12357800
His website is http://pythonav.cn
6将文件中的His替换成My 并将QQ替换成88888888
[root@xuexi3 home]# sed "s/His/My/g" -e "s/12357800/88888888/g" cssed.txt #使用-e 参数多次编辑
sed: can't read s/His/My/g: No such file or directory
My name is maitekai.
I teach linux.
My qq is 88888888
My website is http://pythonav.cn
7在第二行追加内容a字符功能，写入到文件，还得添加-i
[root@xuexi3 home]# sed "2a My linux is good." cssed.txt #在添加的内容里加\n加内容可以添加两行内容
My name is maitekai.
I teach linux.
My linux is good.
My qq is 88888888
My website is http://pythonav.cn
[root@xuexi3 home]# sed "2a My linux is good." cssed.txt -i
[root@xuexi3 home]# cat cssed.txt
My name is maitekai.
I teach linux.
My linux is good.
My qq is 88888888
My website is http://pythonav.cn
8在每一行下面添加一行分隔符
[root@xuexi3 home]# sed "a ------" cssed.txt
My name is maitekai.
------
I teach linux.
------
My linux is good.
------
My qq is 88888888
------
My website is http://pythonav.cn
------
linux 系统中筛选出 IP 地址
[root@xuexi3 ~]# ifconfig #第一步查看
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.102 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::c8ef:f7f6:2949:b8fb prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:72:4f:0f txqueuelen 1000 (Ethernet)
RX packets 6078 bytes 528181 (515.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3901 bytes 428504 (418.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 32 bytes 2592 (2.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 32 bytes 2592 (2.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:11:5c:37 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@xuexi3 ~]# ifconfig ens33 # 查看网卡地址
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.102 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::c8ef:f7f6:2949:b8fb prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:72:4f:0f txqueuelen 1000 (Ethernet)
RX packets 6167 bytes 534925 (522.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3944 bytes 433686 (423.5 KiB)
[root@xuexi3 ~]# ifconfig ens33 | sed -e "2s/^.*inet//" -n -e "2s/net.*$//p" -n #用-e多次编辑加管道符输出
10.0.0.102