25.第五章文本处理三剑客之 sed(一)

2023-11-08 21:40:04

5.文本处理三剑客之 sed

5.1 sed 工作原理

sed 即 Stream EDitor，和 vi 不同，sed是行编辑器

Sed是从文件或管道中读取一行，处理一行，输出一行；再读取一行，再处理一行，再输出一行，直到最后一行。每当处理一行时，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。一次处理一行的设计模式使得sed性能很高，sed在读取大文件时不会出现卡顿的现象。如果使用vi命令打开几十M上百M的文件，明显会出现有卡顿的现象，这是因为vi命令打开文件是一次性将文件加载到内存，然后再打开。Sed就避免了这种情况，一行一行的处理，打开速度非常快，执行速度也很快

参考网站：http://www.gnu.org/software/sed/manual/sed.html

5.2 sed 基本用法

格式：

sed [option]... 'script;script;...' inputfile...

常用选项：

-n 不输出模式空间内容到屏幕，即不自动打印
-e 多点编辑
-f FILE 从指定文件中读取编辑脚本
-r, -E 使用扩展正则表达式
-i.bak 备份文件并原处编辑

#说明:
-ir 不支持
-i -r 支持
-ri 支持
-ni 会清空文件

script格式：

'地址命令'

地址格式：

1. 不给地址：对全文进行处理
2. 单地址：
    #：指定第#行，$：最后一行
    /pattern/：被此处模式(正则表达式)所能够匹配到的每一行
3. 地址范围：
    #,# #从#行到第#行，3，6 从第3行到第6行
    #,+# #从#行到+#行，3,+4 表示从3行到第7行
    /pat1/,/pat2/
    #,/pat/
4. 步进：~
    1~2 奇数行
    2~2 偶数行

命令：

p 打印当前模式空间内容，追加到默认输出之后
Ip 忽略大小写输出
d 删除模式空间匹配的行，并立即启用下一轮循环
! 模式空间中匹配行取反处理
a [\]text 在指定行后面追加文本，支持使用\n实现多行追加
i [\]text 在行前面插入文本
c [\]text 替换行为单行或多行文本
w file 保存模式匹配的行至指定文件
r file 读取指定文件的文本至模式空间中匹配到的行后
= 为模式空间中的行打印行号

搜索替代

s/pattern/string/修饰符 查找替换,支持使用其它分隔符，可以是其它形式：s@@@，s###替换修饰符：
g 行内全局替换
p 显示替换成功的行
w /PATH/FILE 将替换成功的行保存至文件中
I,i 忽略大小写

范例:

[root@rocky8 ~]# sed --help
Usage: sed [OPTION]... {script-only-if-no-other-script} [input-file]...

  -n, --quiet, --silent
                 suppress automatic printing of pattern space
  -e script, --expression=script
                 add the script to the commands to be executed
  -f script-file, --file=script-file
                 add the contents of script-file to the commands to be executed
  --follow-symlinks
                 follow symlinks when processing in place
  -i[SUFFIX], --in-place[=SUFFIX]
                 edit files in place (makes backup if SUFFIX supplied)
  -c, --copy
                 use copy instead of rename when shuffling files in -i mode
  -b, --binary
                 does nothing; for compatibility with WIN32/CYGWIN/MSDOS/EMX (
                 open files in binary mode (CR+LFs are not treated specially))
  -l N, --line-length=N
                 specify the desired line-wrap length for the `l' command
  --posix
                 disable all GNU extensions.
  -E, -r, --regexp-extended
                 use extended regular expressions in the script
                 (for portability use POSIX -E).
  -s, --separate
                 consider files as separate rather than as a single,
                 continuous long stream.
      --sandbox
                 operate in sandbox mode (disable e/r/w commands).
  -u, --unbuffered
                 load minimal amounts of data from the input files and flush
                 the output buffers more often
  -z, --null-data
                 separate lines by NUL characters
  --help
                 display this help and exit
  --version
                 output version information and exit

If no -e, --expression, -f, or --file option is given, then the first
non-option argument is taken as the sed script to interpret.  All
remaining arguments are names of input files; if no input files are
specified, then the standard input is read.

GNU sed home page: <https://www.gnu.org/software/sed/>.
General help using GNU software: <https://www.gnu.org/gethelp/>.
E-mail bug reports to: <bug-sed@gnu.org>.

[root@rocky8 ~]# sed ''
raymond
raymond
boss
boss
linux
linux
^C
#sed默认功能就是读入一行，显示一行，它就是把每一次读入的标准输入放入到内存中，放到模式空间，默认把读入的行进行显示，叫自动打印
#不给地址：对全文进行处理

[root@rocky8 ~]# seq 10 |sed ''
1
2
3
4
5
6
7
8
9
10
#既然支持标准输入，可以用管道进行标准输入

[root@rocky8 ~]# seq 10 |sed 'p' #p 打印
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10

[root@rocky8 ~]#  seq 10 |sed -n 'p' #-n 关闭自动打印
1
2
3
4
5
6
7
8
9
10

[root@rocky8 ~]# seq 10 |sed -n '3p'
3
#指定打印行

[root@rocky8 ~]# seq 10 |sed -n '$p'
10
#$ 打印最后一行

#下面方法都是错误的
[root@rocky8 ~]# seq 10 |sed -n '$-1p'
sed: -e expression #1, char 2: unknown command: `-'
[root@rocky8 ~]# seq 10 |sed -n '($-1)p'
sed: -e expression #1, char 1: unknown command: `('
[root@rocky8 ~]# seq 10 |sed -n '\($-1\)p'
sed: -e expression #1, char 8: unterminated address regex
[root@rocky8 ~]# seq 10 |sed -en '\($-1\)p'
sed: can't read \($-1\)p: No such file or directory

[root@rocky8 ~]# seq 10 |sed -n '2p'
2

[root@rocky8 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.255
        inet6 fe80::20c:29ff:fef9:6ad1  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:f9:6a:d1  txqueuelen 1000  (Ethernet)
        RX packets 2753350  bytes 4032564562 (3.7 GiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 387850  bytes 52488253 (50.0 MiB)
        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 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@rocky8 ~]# ifconfig |sed -n '2p'
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.255

[root@rocky8 ~]# ifconfig eth0 | sed -n '/netmask/p'
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.255
#支持正则表达式

[root@rocky8 ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# sed -n '/^UUID/p' /etc/fstab  #显示UUID开头的行
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# sed -n '/[^#]/p' /etc/fstab #过滤掉空行
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# sed -n '/^[^#]/p' /etc/fstab #过滤掉#开头行和空行
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# sed -n '/^bin/,/^mail/p' /etc/passwd #显示bin开头到mail开头的行
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
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

[root@rocky8 ~]# sed -n '5,/^mail/p' /etc/passwd #显示第5行到mail开头的行
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

[root@rocky8 ~]# seq 10 | sed -n '3,6p' #从第3行到第6行显示
3
4
5
6
[root@rocky8 ~]# seq 10 | sed -n '3,+4p' #从第三行往后加4行显示
3
4
5
6
7
[root@rocky8 ~]# seq 10 | sed -n '3,$p' #从第3行到最后一行显示
3
4
5
6
7
8
9
10

[root@rocky8 ~]# seq 10 |sed -n '1~2p' #1~2 奇数行
1
3
5
7
9
[root@rocky8 ~]# seq 10 |sed -n '2~2p' #2~2 偶数行
2
4
6
8
10
[root@rocky8 ~]# seq 10 |sed '1~2d' #删除奇数行
2
4
6
8
10
[root@rocky8 ~]# seq 10 |sed '2~2d'  #删除偶数行
1
3
5
7
9
[root@rocky8 ~]# seq 10|sed '1,5d' #删除1-5行
6
7
8
9
10

[root@rocky8 ~]# sed -n '/^mail/p' /etc/passwd
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

[root@rocky8 ~]# sed -n '/^MAIL/Ip' /etc/passwd
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
#I 忽略大小写

[root@rocky8 ~]# sed '/UUID/d' /etc/fstab #删除UUID开头的行

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
#d 删除包含的行

[root@rocky8 ~]# sed '1d' /etc/fstab #删除第一行
#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0


[root@rocky8 ~]# sed -n '/^#/!p' /etc/fstab #过滤掉#开头的行

UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0
# !  取反，排除

[root@rocky8 ~]# yum -y install httpd
[root@rocky8 ~]# sed -n '/^[^#]/p' /etc/httpd/conf/httpd.conf #过滤掉#开头的行和空行

[root@rocky8 ~]# sed -n '/^ *#/!p' /etc/httpd/conf/httpd.conf  #过滤掉#前面有空格的行

#过滤掉#开头、空行、和空白字符后有#的行
[root@rocky8 ~]# sed -n '/^$/d;/^[[:space:]]*#/!p' /etc/httpd/conf/httpd.conf

#过滤掉#开头和空行
[root@rocky8 ~]# sed -r '/^(#|$)/d' /etc/httpd/conf/httpd.conf #-r 支持扩展正则表达式

[root@rocky8 ~]# sed '/UUID/a linux' /etc/fstab #在UUID 的下一行插入linux

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
linux
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
linux
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
linux
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0
linux

[root@rocky8 ~]# sed '/UUID/a\  line1\n  line2' /etc/fstab

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
  line1
  line2
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
  line1
  line2
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
  line1
  line2
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0
  line1
  line2
#第一行想要缩进,a 后面加个斜线 ，斜线表示开始

[root@rocky8 ~]# sed '/UUID/w /data/a.txt' /etc/fstab #把UUID开头的行保存到/data/a.txt文件

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# ll /data/a.txt
-rw-r--r-- 1 root root 376 Oct 11 20:03 /data/a.txt               
[root@rocky8 ~]# cat /data/a.txt
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0
# w  找到 保存至文件

[root@rocky8 ~]# sed '/UUID/r /etc/issue' /etc/fstab #在UUID的行下方读入文件/etc/issue

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
\S
Kernel \r on an \m

UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
\S
Kernel \r on an \m

UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
\S
Kernel \r on an \m

UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0
\S
Kernel \r on an \m
#r  把文件读入

[root@rocky8 ~]#  sed '/UUID/=' /etc/fstab #在UUID的行前面加行号

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
12
UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
13
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
14
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
15
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0
#= 等号，加行号

[root@rocky8 ~]# cp /etc/fstab .
[root@rocky8 ~]# sed 's/UUID/uuid/' fstab #把UUID替换成uuid

#
# /etc/fstab
# Created by anaconda on Wed Oct  6 11:16:34 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
uuid=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
uuid=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
uuid=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
uuid=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# sed -n 's/UUID/uuid/p' fstab 
uuid=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
uuid=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
uuid=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
uuid=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

[root@rocky8 ~]# seq 10 |sed -n -e '2p'
2
[root@rocky8 ~]# seq 10 |sed -n -e '2p' -e '6p' #可以两个-e单独分开写
2
6
[root@rocky8 ~]# seq 10 |sed -n -e '2p;6p' #也可以两个写一块用; 分号隔开
2
6
#-e 多点编辑

[root@rocky8 ~]# echo 2p >sed.txt
[root@rocky8 ~]# cat sed.txt
2p
[root@rocky8 ~]# seq 10 |sed -n -f sed.txt
2
#也可以把脚本写入文件，直接调用

范例：

[root@rocky8 ~]# sed ''
rocky
rocky
linux
linux
^C

[root@rocky8 ~]# sed '' /etc/issue
\S
Kernel \r on an \m

[root@rocky8 ~]# sed 'p' /etc/issue
\S
\S
Kernel \r on an \m
Kernel \r on an \m

[root@rocky8 ~]# sed -n '' /etc/issue
[root@rocky8 ~]# sed -n 'p' /etc/issue
\S
Kernel \r on an \m

[root@rocky8 ~]# sed -n '1p' /etc/passwd
root:x:0:0:root:/root:/bin/bash

[root@rocky8 ~]# ifconfig eth0 | sed '2p'
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.255
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.255
        inet6 fe80::20c:29ff:fef9:6ad1  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:f9:6a:d1  txqueuelen 1000  (Ethernet)
        RX packets 2762453  bytes 4043476630 (3.7 GiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 390407  bytes 52879750 (50.4 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@rocky8 ~]# ifconfig eth0 | sed -n '2p'
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.255

[root@rocky8 ~]# sed -n '$p' /etc/passwd
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin

[root@rocky8 ~]# ifconfig eth0 |sed -n '/netmask/p'
        inet 172.31.1.8  netmask 255.255.248.0  broadcast 172.31.7.25

[root@rocky8 ~]# df | sed -n '/^\/dev\/sd/p'
/dev/sda2      104806400 4015200 100791200   4% /
/dev/sda3       52403200  440948  51962252   1% /data
/dev/sda1        1038336  191796    846540  19% /boot

[root@rocky8 ~]# seq 10 > seq.log
[root@rocky8 ~]# sed -e '2d' -e '4d' seq.log
1
3
5
6
7
8
9
10
[root@rocky8 ~]# sed '2d;4d' seq.log
1
3
5
6
7
8
9
10

[root@rocky8 ~]# sed -i.orig '2d;4d' seq.log
[root@rocky8 ~]# cat seq.log.orig 
1
2
3
4
5
6
7
8
9
10
[root@rocky8 ~]# cat seq.log
1
3
5
6
7
8
9
10

[root@rocky8 ~]# seq 10 > seq.log
[root@rocky8 ~]# sed -i.orig '2d;4d' seq.log

[root@rocky8 ~]# sed -i '/^listen 9527/a listen 80 \nlisten 8080' /etc/httpd/conf/httpd.conf

#删除所有以#开头的行
[root@rocky8 ~]# sed -i '/^#/d' fstab

#只显示非#开头的行
[root@rocky8 ~]# sed -n '/^#/!p' fstab

UUID=57f3a077-bb67-42c3-9e6c-bc8a0fed3776 /                       xfs     defaults        0 0
UUID=c72110fc-5dae-470c-9940-97ba978c7dc7 /boot                   xfs     defaults        0 0
UUID=02ae6744-8c28-4c86-b85b-e113c06a834f /data                   xfs     defaults        0 0
UUID=4f387202-0a81-4202-9e12-90d04af4d308 none                    swap    defaults        0 0

#修改网卡配置
[root@rocky8 ~]# sed -Ei.bak '/^GRUB_CMDLINE_LINUX/s/(.*)(")$/\1net.ifnames=0\2/' /etc/default/grub

码农公寓

5.文本处理三剑客之 sed

5.1 sed 工作原理

5.2 sed 基本用法

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