day 18 正则表达式与取出ip地址

傷城~ 2022-01-16 19:35 275阅读 0赞

复习：

特殊符号：

引号

重定向符号

位置

判断

其他符号

通配符 VS 正则表达式

通配符：找出文件名 大部分命令可以使用

正则： 精确的过滤 三剑客使用

正则表达式

基础正则

.\*

## 1.1 找出oldboy.txt中以m或n开头的行 ##

\[root@zs oldboy\]\# grep "^\[mn\]" oldboy.txt

my blog is http://oldboy.blog.51cto.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

![blob.png][]

## 1.2 找出oldboy.txt中以m或n开头并且以m或n结尾的行 ##

\[root@oldboyedu50-lnb /oldboy\]\# grep '^\[mn\]' oldboy.txt

my blog is http://oldboy.blog.51cto.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

\[root@oldboyedu50-lnb /oldboy\]\# grep '^\[mn\]' oldboy.txt|grep '\[mn\] $'

my blog is http://oldboy.blog.51cto.com

![blob.png][blob.png 1]

\[root@oldboyedu50-lnb /oldboy\]\# grep '^\[mn\].\*\[mn\]$' oldboy.txt

my blog is http://oldboy.blog.51cto.com

![blob.png][blob.png 2]

# 第2章 第9个符号\- \[^\] \[^abc\] #

相当于是一个符号（每次匹配1个字符）

## 2.1 找出除了a或除了b或除了c ##

\[root@oldboyedu50-lnb /oldboy\]\# grep '\[^abc\]' oldboy.txt

I am oldboy teacher!

I teach linux.

I like badminton ball ,billiard ball and chinese chess!

my blog is http://oldboy.blog.51cto.com

our size is http://blog.oldboyedu.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

![blob.png][blob.png 3]

## 2.2 \#排除文件中的数字和大小写字母 ##

\[root@oldboyedu50-lnb /oldboy\]\# grep '\[0-Z\]' oldboy.txt

I am oldboy teacher!

I teach linux.

I like badminton ball ,billiard ball and chinese chess!

my blog is http://oldboy.blog.51cto.com

our size is http://blog.oldboyedu.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

![blob.png][blob.png 4]

![blob.png][blob.png 5]

小结：

^ 以...开头的行

$ 以...结尾的行

^$ 空行

. 任意一个字符

\* 0个或多个

.\* 所有

\[\] \[abc\]

\[^\] \[^abc\]

() 小括号

\[\] 中括号

\{\} 大括号 花括号

**扩展正则****（ERE Extented Regular Expression)**

# 第3章 第10个符号\- + #

## 3.1 + 前一个字符连续出现1次或1次以上 ##

0连续出现

\[root@oldboyedu50-lnb /oldboy\]\# egrep '0+' oldboy.txt

my qq is 49000448

not 4900000448.

![blob.png][blob.png 6]

\[root@oldboyedu50-lnb /oldboy\]\# grep -E '0+' oldboy.txt

my qq is 49000448

not 4900000448.

![blob.png][blob.png 7]

\[root@oldboyedu50-lnb /oldboy\]\# grep '0\\+' oldboy.txt

my qq is 49000448

not 4900000448.

![blob.png][blob.png 8]

**有加号和没有加号的区别**：

（**-o****显示过程**）

\[root@oldboyedu50-lnb /oldboy\]\# egrep '0+' oldboy.txt –o （**一次多个**）

000

00000

![blob.png][blob.png 9]

\[root@oldboyedu50-lnb /oldboy\]\# egrep '0' oldboy.txt -o

![blob.png][blob.png 10]

### 3.1.1 \#取出连续出现的小写字母 ###

\[root@oldboyedu50-lnb /oldboy\]\# egrep '\[a-z\]+' oldboy.txt

![blob.png][blob.png 11]

查看过程：

![blob.png][blob.png 12]

# 第4章 第11个符号\- | 或者 #

## 4.1 找oldboy或linux ##

\[root@oldboyedu50-lnb /oldboy\]\# egrep 'oldboy|linux' oldboy.txt

I am oldboy teacher!

I teach linux.

my blog is http://oldboy.blog.51cto.com

our size is http://blog.oldboyedu.com

![blob.png][blob.png 13]

## 4.2 \#先备份 /etc/ssh/sshd\_config 然后 排除 文件中的\#号的行或空行 ##

备份： \[root@zs oldboy\]\# cp /etc/ssh/sshd\_config\{,.bak\}

排除：

\[root@oldboyedu50-lnb /oldboy\]\# egrep -v '^$|\#' /etc/ssh/sshd\_config

Protocol 2

SyslogFacility AUTHPRIV

PasswordAuthentication yes

ChallengeResponseAuthentication no

GSSAPIAuthentication yes

GSSAPICleanupCredentials yes

UsePAM yes

AcceptEnv LANG LC\_CTYPE LC\_NUMERIC LC\_TIME LC\_COLLATE LC\_MONETARY LC\_MESSAGES

AcceptEnv LC\_PAPER LC\_NAME LC\_ADDRESS LC\_TELEPHONE LC\_MEASUREMENT

AcceptEnv LC\_IDENTIFICATION LC\_ALL LANGUAGE

AcceptEnv XMODIFIERS

X11Forwarding yes

Subsystem sftp /usr/libexec/openssh/sftp-server

# 第5章 正则表达式\-坑3- \[^\#^$\] \[^$\] \[^\#$\] #

**\[\]****中** **$ .** **没有特殊含义**

编辑一些符号，然后查看

\[root@oldboyedu50-lnb /oldboy\]\# cat oldboy.txt

I am oldboy teacher!

I teach linux.

I like badminton ball ,billiard ball and chinese chess!

my blog is http://oldboy.blog.51cto.com

our size is http://blog.oldboyedu.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

\+++++\\\\\\\\\\\\!!!!$$$$$$^^^

\#\#\#\#!!!^^^^^$$$$@@@@@\#\#\#\#

![blob.png][blob.png 14]

\[root@oldboyedu50-lnb /oldboy\]\# grep '\[^\#^$\]' oldboy.txt**（执行这条命令相当于是排除\# ^ $ 三个符号）**

I am oldboy teacher!

I teach linux.

I like badminton ball ,billiard ball and chinese chess!

my blog is [http://oldboy.blog.51][http_oldboy.blog.51] cto.com

our size is http://blog.oldboyedu.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

\+++++\\\\\\\\\\\\!!!!$$$$$$^^^

\#\#\#\#!!!^^^^^$$$$@@@@@\#\#\#\#

![blob.png][blob.png 15]

\[root@oldboyedu50-lnb /oldboy\]\# grep '\\.$' oldboy.txt

I teach linux.

not 4900000448.

![blob.png][blob.png 16]

\[root@oldboyedu50-lnb /oldboy\]\# grep '\[.\]$' oldboy.txt

I teach linux.

not 4900000448.

![blob.png][blob.png 17]

# 第6章 正则表达式\-坑4- \[^abc\] vs grep -v #

\[^a-z\] 排除按字符 某个字符 某些字符

grep -v \[a-z\] 排除按行

## 6.1 排除a-z的小写字母 ##

\[root@oldboyedu50-lnb /oldboy\]\# grep '\[^a-z\]' oldboy.txt

I am oldboy teacher!

I teach linux.

I like badminton ball ,billiard ball and chinese chess!

my blog is http://oldboy.blog.51cto.com

our size is http://blog.oldboyedu.com

my qq is 49000448

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

\+++++\\\\\\\\\\\\!!!!$$$$$$^^^

\#\#\#\#!!!^^^^^$$$$@@@@@\#\#\#\#

![blob.png][blob.png 18]

## 6.2 排除含有a-z的行 ##

\[root@oldboyedu50-lnb /oldboy\]\# grep -v '\[a-z\]' oldboy.txt

\+++++\\\\\\\\\\\\!!!!$$$$$$^^^

\#\#\#\#!!!^^^^^$$$$@@@@@\#\#\#\#

![blob.png][blob.png 19]

## 6.3 第12个符号\- () 表示一个整体 反向引用/后向引用 ##

### 6.3.1 找出oldboy或oldbey ###

找共同点：

只差o和e两个字母，将它们作为一个整体 先保护起来，然后使用

\[root@oldboyedu50-lnb /oldboy\]\# egrep 'oldb(o|e)y' oldboy.txt

I am oldboy teacher!

my blog is http://oldboy.blog.51cto.com

our size is http://blog.oldboyedu.com

my god ,i am not oldbey,but OLDBOY!

![blob.png][blob.png 20]

反向引用/后向引用

思路：把你想要的内容保护起来 ()

## 6.4 sed 在 's\#\#\#g' 后两个井号之间使用 \\数字 引用 ##

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456

123456

\[root@oldboyedu50-lnb /oldboy\]\# echo '<123456>'

<123456>

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456

123456

\[root@oldboyedu50-lnb /oldboy\]\# echo '<123456>'

<123456>

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(.\*)\#\\1\#g'

123456

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(.\*)\#<\\1>\#g'

<123456> （**将所有数字作为一个整体，在它们前后加上<>**）

echo 123456

12<34>56

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(34)\#<\\1>\#g'

12<34>56 （**将34作为一个整体，在它们前后加上<>**）

![blob.png][blob.png 21]

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(..)(..)(..)\#\\3\#g'

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(..)(..)(..)\#\\3\\2\#g'

5634

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(..)(..)(..)\#\\3\\2\\1\#g'

563412

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(..)(..)(..)\#\\3<\\2\\1\#g'

\[root@oldboyedu50-lnb /oldboy\]\# echo 123456|sed -r 's\#(..)(..)(..)\#\\3<\\2>\\1\#g'

56<34>12

**第****13****个符号** **\{ \} 0\{n,m\}** **前一个字符至少连续出现了****n****次，最多连续出现****m****次**

a\{n,m\}前一个数字连续出现至少n次最多m次

a\{n\}前一个数字连续出现n次

a\{n,\}前一个数字连续出现至少n次

a\{,m\}前一个数字连续出现最多m次

**过滤出0****至少出现三次，最多出现4****次**

\[root@oldboyedu50-lnb /oldboy\]\# egrep '0\{3,4\}' oldboy.txt

my qq is 49000448

not 4900000448.

\[root@oldboyedu50-lnb /oldboy\]\# egrep '0\{3\}' oldboy.txt

my qq is 49000448

not 4900000448.

![blob.png][blob.png 22]

![blob.png][blob.png 23]

# 第7章 提取×××号练习题： #

\[root@oldboyedu50-lnb /\]\# cat id.txt

金 211324198705244720

万 500224197105168312

任 1231231231oldboy

任 3oldboy

任 lidao97303136098

任 alex2197303136098

任 350182197303oldgir

吕 211282199209113038

孔 150000198309176071

邹 371001197412221284

贺 130185200011215926

杜 362522198711278101

向 14052219961008852X

\[root@oldboyedu50-lnb /oldboy\]\# egrep '\[0-9X\]\{18\}' id.txt

金 211324198705244720

万 500224197105168312

吕 211282199209113038

孔 150000198309176071

邹 371001197412221284

贺 130185200011215926

杜 362522198711278101

向 14052219961008852X

\[root@oldboyedu50-lnb /oldboy\]\# egrep '\[0-9\]\{17\}\[0-9X\]' id.txt

金 211324198705244720

万 500224197105168312

吕 211282199209113038

孔 150000198309176071

邹 371001197412221284

贺 130185200011215926

杜 362522198711278101

向 14052219961008852X

BRE

1. ^

2. $

3. ^$

4. .（点）

5. \*

6. .\*

7. \[\] \[a-z\] \[A-Z\] \[0-9\]

grep/egrep \[a-Z\]

8. \[^\]

ERE小结

1.+

2.|

3.()

4.\{\}

5. ?

# 第8章 取出网卡的ip地址 #

ip a s eth0

ip address show eth0

某一行的某一部分

1.定位 取出某一行

2.sed/awk 取出想要的内容

方法1

\[root@oldboyedu50-lnb /oldboy\]\# ip a s eth0 |awk 'NR==3'|awk -F"\[ /\]+" '\{print $3\}'

10.0.0.200

\[root@oldboyedu50-lnb /oldboy\]\#

![blob.png][blob.png 24]

## 8.1 取出ifconfig eth0 ip地址和子网掩码 ##

\[root@oldboyedu50-lnb /oldboy\]\# ifconfig eth0 |awk 'NR==2'

inet addr:10.0.0.200 Bcast:10.0.0.255 Mask:255.255.255.0

\[root@oldboyedu50-lnb /oldboy\]\# ifconfig eth0 |awk 'NR==2' |awk -F"\[ :\]+" '\{print $4,$NF\}'

10.0.0.200 255.255.255.0

![blob.png][blob.png 25]

\[root@oldboyedu50-lnb /oldboy\]\# ifconfig eth0 |awk 'NR==2'

inet addr:10.0.0.200 Bcast:10.0.0.255 Mask:255.255.255.0

\[root@oldboyedu50-lnb /oldboy\]\# ifconfig eth0 |awk 'NR==2' |awk -F"addr:|Bcast:" '\{print $2\}'

10.0.0.200

![blob.png][blob.png 26]

\[root@zs oldboy\]\# ifconfig eth0 |awk 'NR==2' |awk -F"addr:|Mask:|Bcast:" '\{print $2,$NF\}'

10.0.0.200 255.255.255.0

\[root@zs oldboy\]\#

![blob.png][blob.png 27]

![blob.png][blob.png 28]

![blob.png][blob.png 29]

小结：

1.取出ip地址

2.awk方法 \-F (指定分隔符)

总结：

1.正则 BRE ERE

2.排除文件中的空行或以\#开头的行 grep sed awk

3.取出网卡ip地址

ifconfig eth0

ip a

awk

sed

转载于:https://blog.51cto.com/13859679/2154274

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[http_oldboy.blog.51]: http://oldboy.blog.51/
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