文本处理工具——sed进阶

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一sed的搜索替代

 

（一）常见的和替代相关的选项

 

 

搜索替代，和vim的写法很像

 

s///：查找替换,支持使用其它分隔符，[email protected]@@，s###

 

p: 显示替换成功的行，就是打印。


w /PATH/TO/SOMEFILE ：将替换成功的行保存至文件中

 

替换标记：


g: 行内全局替换和博客园里面的替换全部是一样的效果

 

 

技术图片

 

 

 

 

注意搜索最好不要使用斜线/，因为linux系统里面有很多斜线，比如目录或者文件路径。

前面搜索的是模式，使用正则表达式$,后面替换的内容就不要了。

 

 

（1）s///：查找替换,支持使用其它分隔符，[email protected]@@，s###

把/bin/bash结尾的行替换为/sbin/nologin结尾


[[email protected] ~]# sed  ‘[email protected]/bin/[email protected]/sbin/[email protected]‘    /etc/passwd
root:x:0:0:root:/root:/sbin/nologin
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
wang:x:1000:1000:wang:/home/wang:/sbin/nologin

 

 

 

 

 

 

 

 注意没有加-i都只是测试而已，没有真正修改文件里面的内容

在ansible里面也是一样，有测试和真正执行。

[[email protected] ~]# cat  /etc/passwd  -n
     1    root:x:0:0:root:/root:/bin/bash
     2    bin:x:1:1:bin:/bin:/sbin/nologin
     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
     7    shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
     8    halt:x:7:0:halt:/sbin:/sbin/halt
     9    mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
    10    operator:x:11:0:operator:/root:/sbin/nologin
    11    games:x:12:100:games:/usr/games:/sbin/nologin
    12    ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
    13    nobody:x:99:99:Nobody:/:/sbin/nologin
    14    systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
    15    dbus:x:81:81:System message bus:/:/sbin/nologin
    16    polkitd:x:999:998:User for polkitd:/:/sbin/nologin
    17    sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
    18    postfix:x:89:89::/var/spool/postfix:/sbin/nologin
    19    wang:x:1000:1000:wang:/home/wang:/bin/bash

 

 

 

 

 

 

（2） -r: 支持使用扩展正则表达式

-r, --regexp-extended

use extended regular expressions in the script.

1）

(/bin/bash)$表示(/bin/bash)$行尾是/bin/bash

[[email protected] ~]# sed    -r    ‘[email protected](/bin/bash)[email protected]######@‘    /etc/passwd   
root:x:0:0:root:/root:######
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
wang:x:1000:1000:wang:/home/wang:######

 

 

 

 

 

 

2）使用正则表达式里面的后向引用

在bash的前面追加了###

文件未修改内容

[[email protected] ~]# cat  /etc/passwd   
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
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
wang:x:1000:1000:wang:/home/wang:/bin/bash

 

 

 

 

 

对第1行修改，忽略了命令

[[email protected] ~]# sed    -r    ‘[email protected](/bin/bash)[email protected]######\\[email protected]‘    /etc/passwd   
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
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
wang:x:1000:1000:wang:/home/wang:######/bin/bash

 

 

 

 

 

不加括号会报错，因为是一个整体

[[email protected] ~]# sed    -r    ‘[email protected]/bin/[email protected]######\\[email protected]‘    /etc/passwd   
sed: -e expression #1, char 22: invalid reference \\1 on `s‘ command‘s RHS

 

 

 

 

 

3）在bash的后面追加

[[email protected] ~]#  sed    -r    ‘[email protected](/bin/bash)[email protected]\\1*******@‘    /etc/passwd
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
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
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:Saslauthd user:/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
abrt:x:173:173::/etc/abrt:/sbin/nologin
haldaemon:x:68:68:HAL daemon:/:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin
radvd:x:75:75:radvd user:/:/sbin/nologin
qemu:x:107:107:qemu user:/:/sbin/nologin
ident:x:98:98::/:/sbin/nologin

 

 

 

 

[[email protected] ~]# sed    -r    ‘[email protected](/bin/bash)[email protected]######\\1*******@‘    /etc/passwd   
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
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
wang:x:1000:1000:wang:/home/wang:######/bin/bash*******

 

 

 

 

 

 

 

 

对配置文件进行搜索替换

selinux的配置文件，未修改

[[email protected] ~]# 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=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

 

 

 

 

 

 把SELINUX=disabled这对键值对修改为SELINUX=permissive

[[email protected] ~]# sed  ‘[email protected][email protected][email protected]‘    /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=permissive
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

 

 

 

 

 

担心把注释也替换了，那么就使用脱义字符定位到行首，那么就修改以SELINUX开头的

[[email protected] ~]# sed  ‘[email protected]^[email protected][email protected]‘    /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=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

 

 

 

 

 

 

 

 

 

示例1——取出虚拟机的网络接口信息的第2行IP地址

 

 

 

显示虚拟机的网络接口信息

[[email protected] ~]# ifconfig    ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255
        inet6 fe80::b029:2522:876f:5456  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:fc:69:f8  txqueuelen 1000  (Ethernet)
        RX packets 10428  bytes 978015 (955.0 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5654  bytes 737168 (719.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 

 

 

 

 

法1：

解决思路：

点心.*是任意字符串

sed ‘[email protected]*inet @@‘  中.*inet表示IP地址前面的内容，包括前面的空白，也就是任意的字符串。

@@表示无内容，也就把上述内容删除了

 

 

技术图片

 

 

再一次搜索替代，把IP地址后面的内容进行替换，替换成空，也就是删除。

对上面的操作一个词形容就是掐头去尾，注意要关闭自动打印

 

 

 

打印第2行的内容1遍

[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘
        inet 192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

 先掐头

 再一次搜索替代，把IP地址后面的内容进行替换，替换成空，也就是删除。

因为只有1行，只出现1处，可以加g，也可以不加

[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   ‘[email protected]*inet @@g‘
192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255
[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   ‘[email protected]*inet @@‘
192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

 

 后去尾

去尾的方法和掐头是一样的，掐头是把前面不要的去掉，去尾是把后面不要的去掉

成功提取出了IP地址



[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   ‘[email protected]*inet @@‘   |   sed  ‘[email protected]*@@‘
192.168.137.72  
[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   ‘[email protected]*inet @@‘   |   sed  ‘[email protected]* @@‘
192.168.137.72  192.168.137.255
[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   ‘[email protected]*inet @@‘   |   sed  ‘[email protected]*@ @‘
192.168.137.72

 

 

 

 

 

 

 

法2：

简化上面的步骤

搜索替换，使用正则表达式的后向引用，\\1就是（.*）的内容，也就是IP地址了。

简而言之搜索的出来的内容替换成想要的IP地址

[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   -r   ‘[email protected]*inet(.*)netmask.* @\\[email protected]‘   
 192.168.137.72  192.168.137.255
[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   -r   ‘[email protected]*inet(.*)netmask.*@\\[email protected]‘   
 192.168.137.72

 

 

 

 

[[email protected] ~]# ifconfig    ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.137.73  netmask 255.255.255.0  broadcast 192.168.137.255
        inet6 fe80::20c:29ff:fe90:2d58  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:90:2d:58  txqueuelen 1000  (Ethernet)
        RX packets 47147  bytes 4270150 (4.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 37301  bytes 4624878 (4.4 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 

 

 

 

 

 

 

注意空格很重要，inet和192.168.137.72之间是有空格的，所以命令里面也要有空格

平时要注意细节

[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   -r   ‘[email protected]*inet(.*)netmask.*@\\[email protected]‘   
 192.168.137.72  
[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   -r   ‘[email protected]*inet (.*)netmask.*@\\[email protected]‘   
192.168.137.72  
[[email protected] ~]# ifconfig    ens33   |   sed   -n   ‘2p‘
        inet 192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

 

 

 

 

法3：

最简步骤，对ed的选项进行组合

和法2一样，使用后向引用，就是前面使用括号，后面\\1这样会更方便

注意sed的选项是可以组合的

[[email protected] ~]#  ifconfig    ens33   |   sed   -n   ‘2p‘  |   sed   -r   ‘[email protected]*inet (.*) netmask.*@\\[email protected]‘   
192.168.137.72 
[[email protected] ~]#  ifconfig    ens33   |     sed  -n   -r   ‘[email protected]*inet (.*) netmask.*@\\[email protected]‘ 
#使用一次管道传输就可以  
192.168.137.72

 

 

 

 

 

不指明第2行一样可以显示，因为只有第2行可以匹配的

[[email protected] ~]# ifconfig    ens33   |     sed  -n   -r   ‘[email protected]*inet (.*) netmask.*@\\[email protected]‘ 
192.168.137.72

 

 

 

 

 

[[email protected] ~]# ifconfig  ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255
        inet6 fe80::20c:29ff:fefc:69f8  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:fc:69:f8  txqueuelen 1000  (Ethernet)
        RX packets 8980  bytes 724071 (707.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4108  bytes 571189 (557.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[[email protected] ~]#  ifconfig    ens33   |     sed     -r   ‘[email protected]*inet (.*) netmask.*@\\[email protected]‘   
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
192.168.137.72 
        inet6 fe80::20c:29ff:fefc:69f8  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:fc:69:f8  txqueuelen 1000  (Ethernet)
        RX packets 8984  bytes 724483 (707.5 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4111  bytes 572131 (558.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 

 

 

 

[[email protected] ~]#  ifconfig    ens33   |     sed     -r   ‘[email protected]*inet (.*) netmask.*@\\[email protected]‘   
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
192.168.137.72 
        inet6 fe80::b029:2522:876f:5456  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:fc:69:f8  txqueuelen 1000  (Ethernet)
        RX packets 11742  bytes 1101659 (1.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 6340  bytes 813708 (794.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 

 

 

 

 

 

 

 

法4

先取出第2行，也就是除了第2行其他的都删除

 在命令前取反

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

[[email protected] ~]# ifconfig   ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255
        inet6 fe80::20c:29ff:fefc:69f8  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:fc:69:f8  txqueuelen 1000  (Ethernet)
        RX packets 11953  bytes 958598 (936.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5525  bytes 726003 (708.9 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2d‘
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet6 fe80::20c:29ff:fefc:69f8  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:fc:69:f8  txqueuelen 1000  (Ethernet)
        RX packets 11961  bytes 959310 (936.8 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5530  bytes 727141 (710.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2!d‘
        inet 192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

 

 

把192.168.137.72前面的所有内容替换为空

注意//之间是没有空格的

使用分号就相当于在命令行同时写上多条命令

[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2!d;s/.*inet //‘
192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

 

 

使用分号就相当于在命令行同时写上多条命令

[[email protected] ~]# ls  ;echo 
a  access_log  anaconda-ks.cfg  c  shell_scripts  _wang.html

 

 

 

 

 

[[email protected] ~]# ls;pwd
anaconda-ks.cfg  ~
/root

 

 

 

 

把192.168.137.72后面的所有内容替换为空

 注意.*//是没有空格的。

使用分号就相当于在命令行同时写上多条命令

成功提取出了IP地址

[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2!d;s/.*inet //;s/netmask .*//‘
192.168.137.72

 

 

 

 

 

 注意下面都是有空格的，空格是很关键的，要实现精准匹配

[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2!d;s/.*inet //;s/netmask .* //‘
192.168.137.72  192.168.137.255
[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2!d;s/.*inet //‘
192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

技术图片

 

 

 

 

[[email protected] ~]# ifconfig   ens33   |   sed   -r    ‘2!d;s/.*inet //;s/netmask .*    //‘
192.168.137.72  netmask 255.255.255.0  broadcast 192.168.137.255

 

 

 

 

 

 

 

 

示例2——显示虚拟机使用的光盘的版本号

使用正则表达式的后向引用

注意空格，哪怕是空一格和两格都是有区别的。

 显示几格那么在命令里面也要写几格

不自动打印，并且使用正则表达式的后向引用

和示例1的套路是一样的，括号里面是要显示的内容，后面引用的内容就是括号里面的

[[email protected]s72 ~]# cat /etc/centos-release
CentOS Linux release 7.5.1804 (Core) 
[[email protected] ~]# sed  -rn    ‘[email protected]*release  (.*)\\..*@\\[email protected]‘     /etc/centos-release
[[email protected] ~]# sed  -rn    ‘[email protected]*release (.*)\\..*@\\[email protected]‘     /etc/centos-release
7.5

 

 

 

 

为了避免出现两位数，比如10版本要写+，表示匹配一个或者一个以上的非点

注意-r和-n选项的前后位置没关系

[[email protected] ~]# sed  -rn    ‘[email protected]*release  ([^.]+)\\..*@\\[email protected]‘     /etc/centos-release
[[email protected] ~]# sed  -rn    ‘[email protected]*release ([^.]+)\\..*@\\[email protected]‘     /etc/centos-release
7
[[email protected] ~]# sed  -r  -n    ‘[email protected]*release ([^.]+)\\..*@\\[email protected]‘     /etc/centos-release
7
[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.]+)\\..*@\\[email protected]‘     /etc/centos-release
7

 

 

 

 

 

 

 

因为是非点了，外面就不需要写上点

下面是最简洁的最终写法，是所有Linux版本通用的，注意把多余的去掉

[[email protected] ~]# cp  /etc/centos-release   centos-release
[[email protected] ~]# vim centos-release
[[email protected] ~]# cat  centos-release 
CentOS Linux release 17.5.1804 (Core)

 

 

 

[[email protected] ~]# sed -nr  "[email protected]* release([^.]+).*@\\[email protected]"  centos-release 
 17

 

 

 

[[email protected] ~]# sed -nr  "[email protected]* release([^.]+).*@\\[email protected]"  /etc/centos-release 
 7
[[email protected] ~]# cat /etc/centos-release
CentOS Linux release 7.5.1804 (Core)

 

 

 

 

 

 

测试写法：

[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.]+)\\..*@\\[email protected]‘     /etc/centos-release
7
[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.])\\..*@\\[email protected]‘     /etc/centos-release
7
[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.]).*@\\[email protected]‘     /etc/centos-release
7
[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.]+).*@\\[email protected]‘     /etc/centos-release
#因为是非点了，外面就不需要写上\\.
7

 

 

 

 

 

 

 

修改版本，把之前的版本7修改成10，非点就是两位数了。

如果不加上+就只会显示一位数

[[email protected] ~]# cat  /etc/centos-release
CentOS Linux release 10.5.1804 (Core) 
[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.]).*@\\[email protected]‘     /etc/centos-release
1

 

 

 

 

 

这也是为什么要在括号里面加上+

在数据库版本里面，有5版本的，也有10版本的就可以使用到这种版本判断的方法了。

做事要考虑周到

[[email protected] ~]# sed  -n  -r   ‘[email protected]*release ([^.]+).*@\\[email protected]‘     /etc/centos-release
10

 

 

 

 

 

 

示例3——进行版本判断，如果符合版本就执行相关命令

 

下面是内核版本，涉及到了18启动和内核管理知识

过滤有两种方法

法1：

[[email protected] ~]# grep  linux16  /etc/grub2.cfg 
    linux16 /vmlinuz-3.10.0-862.el7.x86_64 root=UUID=5998ead0-b370-4859-9153-ecf4e2b9dd84 ro rhgb quiet LANG=en_US.UTF-8
    linux16 /vmlinuz-0-rescue-cb26ac281315402a9928e9a4c3bedfcd root=UUID=5998ead0-b370-4859-9153-ecf4e2b9dd84 ro rhgb quiet

 

 

 

 

法2：

[[email protected] ~]# cat  /etc/grub2.cfg   |   grep  "linux16" 
    linux16 /vmlinuz-3.10.0-862.el7.x86_64 root=UUID=5998ead0-b370-4859-9153-ecf4e2b9dd84 ro rhgb quiet LANG=en_US.UTF-8
    linux16 /vmlinuz-0-rescue-cb26ac281315402a9928e9a4c3bedfcd root=UUID=5998ead0-b370-4859-9153-ecf4e2b9dd84 ro rhgb quiet

 

 

 

 

[[email protected] ~]# cat  /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

 

按照上面的最简方法先把版本号取出来，并且设置版本号为变量名

（）里面的内容就是进行分组

\\1表示括号里面的内容，\\1就相当于sed里面的-a\\，后面可以添加内容。

LINUX=相当于grep   LINUX=,作用是过滤出要修改的那行

[[email protected] ~]# sed   -rn      ‘[email protected](.*LINUX=".*)" @\\1 xxxxxx @p‘         /etc/default/grub 
[[email protected] ~]# sed   -rn      ‘[email protected](.*LINUX=".*)"@\\1 xxxxxx @p‘         /etc/default/grub 
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx 
[[email protected] ~]# sed   -rn      ‘[email protected](.*LINUX=".*)"@\\1 xxxxxx" @p‘         /etc/default/grub 
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"

 

 

 

 

 

修改版本了，修改成系统默认的版本7

[[email protected] ~]# sed  -nr   ‘[email protected]*release([^.]+).*@\\1 @p‘    /etc/centos-release
 10 
[[email protected] ~]# vim  /etc/centos-release
[[email protected] ~]# sed   -n   ‘s/10/7/p‘   /etc/centos-release
CentOS Linux release 7.5.1804 (Core) 
[[email protected] ~]# cat  /etc/centos-release
CentOS Linux release 10.5.1804 (Core) 
[[email protected] ~]# sed  -i   -n   ‘s/10/7/p‘   /etc/centos-release
[[email protected] ~]# cat  /etc/centos-release
CentOS Linux release 7.5.1804 (Core)

 

 

 

 

 

 

法1：

写成脚本

[[email protected] ~]#  cat  /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

完整脚本

[[email protected] ~]# cat  reset.sh 
#!/bin/bash
version=`sed  -nr   ‘[email protected]*release([^.]+).*@\\1 @p‘    /etc/centos-release`
[   $version  =  7   ]    &&      sed   -rn      ‘[email protected](.*LINUX=".*)"@\\1 xxxxxx" @p‘         /etc/default/grub    ||   exit   2

 

 

 

 

 执行结果

[[email protected] ~]# bash  reset.sh
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"

 

 

 

 

 

 

 

 法2：

 脚本内容

[[email protected] ~]# cat  reset1.sh 
#!/bin/bash
version=`sed  -nr   ‘[email protected]*release([^.]+).*@\\1 @p‘    /etc/centos-release`
if   [   $version    -eq   7  ];then

     sed   -r   ‘[email protected](quiet)@\\1 [email protected]‘   /etc/default/grub 
else
     echo   "the   OS  is   $version,there  is  no   target  file."
     exit   2
fi

 

 

 

 

 

 执行结果

[[email protected] ~]# bash  reset1.sh 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

 

[[email protected] ~]# sed   -nr   ‘[email protected](quiet)@\\1 [email protected]‘   /etc/default/grub 
[[email protected] ~]#  sed   -r   ‘[email protected](quiet)@\\1 [email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

[[email protected] ~]# cat    /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

法3：

s前面加正则表达式过滤出有LINUX的行/LINUX/，模式匹配的单地址

[[email protected] ~]# sed  -r  ‘/LINUX/[email protected]("$)@ xxxxxx\\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 xxxxxx\\1是显示的内容，前面要有空格才可以和前面的隔开？

[[email protected] ~]# sed  -r  ‘/LINUX/[email protected]("$)@xxxxxx\\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quietxxxxxx"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

 锚定到冒号结尾

[[email protected] ~]# sed  -r  ‘/LINUX/[email protected]("$)@xxxxxx \\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quietxxxxxx "
GRUB_DISABLE_RECOVERY="true"
[[email protected] ~]# sed  -r  ‘/LINUX/[email protected]("$) @xxxxxx\\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"

 

 

 

最佳命令

[[email protected] ~]#  sed  -r  ‘/LINUX/[email protected]("$)@   xxxxxx \\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet   xxxxxx "
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

 

 

以下方法都不能

[[email protected] ~]#  sed  -r  ‘/LINUX/[email protected](‘ ‘$)@   xxxxxx \\[email protected]‘   /etc/default/grub 
sed: -e expression #1, char 10: unterminated `s‘ command
[[email protected] ~]#  sed  -r  ‘/LINUX/[email protected](‘$)@   xxxxxx \\[email protected]‘   /etc/default/grub 
-bash: syntax error near unexpected token `)‘
[[email protected] ~]#  sed  -r  ‘/LINUX/[email protected](" "$)@   xxxxxx \\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
[[email protected] ~]#  sed  -r  ‘/LINUX/[email protected](" "$)@   xxxxxx \\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
[[email protected] ~]#  sed  -r  ‘/LINUX/[email protected](""$)@   xxxxxx \\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

 

 

法4

[[email protected] ~]# sed  -r   ‘6s/("$)/ xxxxxx\\1/‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"
GRUB_DISABLE_RECOVERY="true"
[[email protected] ~]# sed  -r   ‘[email protected]("$)@ xxxxxx\\[email protected]‘   /etc/default/grub 
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet xxxxxx"
GRUB_DISABLE_RECOVERY="true"

 

 

 

 

 

 

 

 

示例4——取目录的基名

 

利用搜索替代以及正则表达式里的分组取基名和目录名

 

使用@作为分隔符

目录是/etc/sysconfig/network-scripts/

[[email protected] ~]# ll  /etc/sysconfig/network-scripts/  -d
drwxr-xr-x. 2 root root 4096 Apr 15 17:18 /etc/sysconfig/network-scripts/

 

 

 

 

 

基名也就是文件名

[[email protected] ~]# basename   /etc/sysconfig/network-scripts/
network-scripts

 

 

 

 

目录名

[[email protected] ~]# dirname   /etc/sysconfig/network-scripts/
/etc/sysconfig

 

 

 

 

sed执行结果，使用了后向引用

[[email protected] ~]# echo   "/etc/sysconfig/network-scripts/"   |   sed   -rn    ‘[email protected]*/(network-scripts).*/@\\[email protected]‘
network-scripts
[[email protected] ~]# echo   "/etc/sysconfig/network-scripts/"   |   sed   -rn    ‘[email protected]*(network-scripts).*@\\[email protected]‘
network-scripts

[[email protected] ~]# echo   "/etc/sysconfig/network-scripts/"   |   sed   -rn    ‘[email protected]*(/network-scripts/).*@\\[email protected]‘
/network-scripts/

 

 

 

 

 法2：

.+其中.表示任意一个字符，+表示一个或者一个以上的字符，所以（.+）任意一个以上的字符，两者是并的关系。

？表示0或0个以上，/?就表示反斜线/可有可无

\\1引用括号里面的内容

[[email protected] ~]# echo   "/etc/sysconfig/network-scripts/"   |   sed   -rn    ‘[email protected]*/(.+)/[email protected]\\[email protected]‘
network-scripts/

 

 

 

 

创建两个分组(.*/)和(.+)/?，使用正则表达式的后向引用

[[email protected] ~]#  echo   "/etc/sysconfig/network-scripts/"   |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
/etc/sysconfig/
[[email protected] ~]#  echo   "/etc/sysconfig/network-scripts/"   |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
network-scripts/

 

 

 

 

 

 对其他目录进行测试，根目录是行不通的

[[email protected] ~]# echo   ‘/‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
[[email protected] ~]# echo   ‘/‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘

 

 

 

 

 

目录名

[[email protected] ~]# echo   ‘/root‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
/
[[email protected] ~]# echo   ‘/root/.ssh/‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
/root/
[[email protected] ~]# echo   ‘/root/.bashrc‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
/root/

 

 

 

 

基名

[[email protected] ~]# echo   ‘/root‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
root
[[email protected] ~]# echo   ‘/root/.ssh/‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
.ssh/
[[email protected] ~]# echo   ‘/root/.bashrc‘     |   sed   -rn    ‘[email protected](.*/)(.+)/[email protected]\\[email protected]‘
.bashrc

 

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