sed 是一种流编辑器，它一次处理一行内容。处理时，把当前处理的行存储在临时缓冲区中，称为“模式空间”（pattern space ），接着用sed 命令处理缓冲区中的内容，处理完成后，把缓冲区的内容送往屏幕。接着处理下一行，这样不断重复，直到文件末尾。文件内容并没有改变，除非你使用重定向存储输出。Sed 主要用来自动编辑一个或多个文件, 简化对文件的反复操作, 编写转换程序等
[root@localhost fsy]# sed -n ‘3p’ /etc/passwd // 只打印第三行
daemon:x:2:2:daemon:/sbin:/sbin/nologin
[root@localhost fsy]# sed -n ‘2p’ // 只多输出了第二行
aaa
bbb
bbb
accc^H^[[3~
ssdfs
fdfd
dds
[root@localhost fsy]# sed -n ‘2p’ < /etc/passwd // 用sed实现标准输入
bin:x:1:1:bin:/bin:/sbin/nologin
[root@localhost fsy]# sed ‘3,6=’ passwd
[root@localhost fsy]# cat /etc/passwd | sed -n ‘2p’
bin:x:1:1:bin:/bin:/sbin/nologin
[root@localhost fsy]# seq 10
1
2
3
4
5
6
7
8
9
10
[root@localhost fsy]# seq 10 | sed -n ‘5p’
5
sed可以对输出做一些处理，而不是只处理文件
[root@localhost ~]# ifconfig | sed -n 2p
inet addr:192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
[root@localhost fsy]# cat -n passwd // 空行加行号
[root@localhost fsy]# cat -b passwd // 空行不加行号
[root@localhost fsy]# sed -n ‘/^root/p’ passwd // 打印包含root的行
root:x:0:0:root:/root:/bin/bash
[root@localhost fsy]# sed -n ‘10,20p’ passwd // 打印第10行到第20行的内容
[root@localhost fsy]# sed -n ’10,+20p’ passwd // 打印第10行到第30行的内容
地址定界
[root@localhost fsy]# sed -n ‘/^h/,/^s/p’ passwd // 打印h开头的行到s开头的行
[root@localhost fsy]# sed -n ’10,/^s/p’ passwd
[root@localhost fsy]# sed -n ‘/^s/,40p’ passwd
步进
[root@localhost fsy]# seq 10| sed -n ‘1~2p’ // 取奇数行
1
3
5
7
9
[root@localhost fsy]# seq 10 |sed -n ‘2~2p’
2
4
6
8
10
[root@localhost ~]# seq 10 |sed ‘2~2d’
1
3
5
7
9
[root@localhost fsy]# cat passwd | sed ‘3,6a ==========================’
[root@localhost fsy]# cat passwd | sed ‘3~6a ==========================’
[root@localhost fsy]# cat passwd | sed ‘3,6a\ ==========================’
[root@localhost fsy]# cat passwd | sed ‘3,6i\ ==========================’ // 在前面插
[root@localhost fsy]# cat passwd | sed ‘3,6c\ ==========================’ // 替代
[root@localhost fsy]# cat passwd | sed ‘3,6a\ ==========================\n +++++++++++++++++++++++’ // 插入两行
[root@localhost fsy]# cat passwd2 | sed -n ‘3,6w ff’
[root@localhost fsy]# cat ff
3 daemon:x:2:2:daemon:/sbin:/sbin/nologin
4 adm:x:3:4:adm:/var/adm:/sbin/nologin
5 lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
6 sync:x:5:0:sync:/sbin:/bin/sync
[root@localhost fsy]# cat passwd2 | sed ‘3,6r /etc/issue’
[root@localhost fsy]# sed -n ‘3,6!p’ passwd2 // 取反
[root@localhost fsy]# seq 10 |sed -n ‘2~2!p’
[root@localhost fsy]# sed ‘2d’ f1
1
3
4
5
6
7
8
9
10
[root@localhost fsy]# sed -i ‘2d’ f1 // 真的把文件给改了
[root@localhost fsy]# cat f1
1
3
4
5
6
7
8
9
10
[root@localhost fsy]# sed -i.txt ‘2d’ f1 // 先做备份再修改文件
[root@localhost fsy]# cat f1.txt
1
2
3
4
5
6
7
8
9
10
搜索替代
[root@localhost fsy]# sed ‘s/root/Root/’ passwd
[root@localhost fsy]# sed ‘s/root/Root/g’ passwd
[root@localhost fsy]# sed -n ‘s/root/Root/gp’ passwd // 只显示替代成功的行
Root:x:0:0:Root:/Root:/bin/bash
operator:x:11:0:operator:/Root:/sbin/nologin
[root@localhost fsy]# sed -n ‘s/root/Root/w p1’ passwd // 把结果保存到p1文件
[root@localhost fsy]# cat p1
Root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/Root:/sbin/nologin
[root@localhost fsy]# sed -n ‘s/root/Root/gw p1’ passwd
[root@localhost fsy]# cat p1
Root:x:0:0:Root:/Root:/bin/bash
operator:x:11:0:operator:/Root:/sbin/nologin
[root@localhost fsy]# sed -i.bak ‘s/6.9/9.9/g’ /etc/centos-release
[root@localhost fsy]# cat /etc/centos-release
CentOS release 9.9 (Final)
[root@localhost fsy]# cat /etc/selinux/config
This file controls the state of SELinux on the system.
SELINUX= can take one of these three values:
enforcing – SELinux security policy is enforced.
permissive – SELinux prints warnings instead of enforcing.
disabled – No SELinux policy is loaded.
SELINUX=enforcing
SELINUXTYPE= can take one of these two values:
targeted – Targeted processes are protected,
mls – Multi Level Security protection.
SELINUXTYPE=targeted
[root@localhost fsy]# sed ‘s/SELINUX=enforcing/SELINUX=disabled/’ /etc/selinux/config
[root@localhost fsy]# sed -i ‘s/SELINUX=enforcing/SELINUX=disabled/’ /etc/selinux/config
46分钟有总结
[root@localhost fsy]# sed -n ‘/^$/=’ /etc/fstab // 显示空行的行号
1
19
[root@localhost fsy]# sed -n -e ‘/^s/=’ -e ‘/^U/p’ /etc/fstab
UUID=9341e6da-5470-4df8-89c5-bfbc3a689d8d / ext4 defaults 1 1
UUID=12c88f0f-aa56-4be1-9c87-eaf0cf524e75 /app ext4 defaults 1 2
UUID=20192758-4252-4bf6-83d4-52da93ffdab4 /boot ext4 defaults 1 2
UUID=567c9b8b-5207-4a4c-8548-9f5b6ee49c3a /home ext4 defaults 1 2
UUID=3ac9cd7c-8d23-43a6-a550-9f93df25f5cf swap swap defaults 0 0
16
UUID=”5263027d-f571-4c4a-98d8-930e41e0e265″ /home ext4 usrquota,grpquota 0 0
[root@localhost ~]# sed -n ‘/^$/=’ -e ‘/^U/=’ /etc/fstab
sed: can’t read /^$/=: No such file or directory
9
10
11
12
13
18
[root@localhost ~]# sed -n -e ‘/^$/=’ -e ‘/^$/p’ /etc/fstab
1
19
4
[root@localhost ~]# ifconfig|sed -n 2p|sed -e ‘s@.r:@@’
192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
[root@localhost ~]# ifconfig|sed -n 2p|sed -e ‘s@.r:@@’
192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
[root@localhost ~]# ifconfig|sed -n 2p|sed -e ‘s@.r:@@’
192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
[root@localhost ~]# ifconfig|sed -n 2p|sed -e ‘s@.r:@@’ -e ‘s@B.@@’
192.168.1.128
[root@localhost ~]# ifconfig|sed -n 2p|sed -e ‘s@.r:@@’ -e ‘s@B.@@’
192.168.1.128
[root@localhost ~]# ifconfig|sed -n 2p|sed -e ‘s@.r:@@’ -e ‘s@B.@@’
192.168.1.128
[root@localhost ~]# ifconfig | sed -e ‘/Bcast/s/.r://’ -e ‘/Bcast/s/B.//’ // 多点替代
[root@localhost ~]# ifconfig | sed -e ‘/Bcast/s/.r://’ -e ‘/Bcast/s/B.//’
[root@localhost ~]# ifconfig eth0 | sed -e ‘s/.inet addr://’ -e ‘/Bcast/s/B.//’ -n -e 2p
192.168.1.128
[root@localhost ~]# ifconfig |sed -e ‘s@.addr:@@’ -e ‘s@Bcast:.@@’ -n -e 2p
192.168.1.128
取基名
echo /etc/sysconfig/network-scripts/ |sed -r ‘s@(^/./)([^/]+/?)@\2@’
取目录名
echo /etc/sysconfig/network-scripts/ |sed -r ‘s@(^/.*/)([^/]+/?)@\1@’
对/etc/fstab非#开头的加注释
sed -r ‘s/(^[^#])/#\1/’ /etc/fstab
sed -r ‘s/^[^#]/#&/’ /etc/fstab
下面是sed高级用法
原创文章，作者：fsy，如若转载，请注明出处：http://www.178linux.com/74562
