linux正则使用

特殊符号

#创建一个文件 拷贝下面内容到文件中
touch regular_express.txt
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文件内容

"Open Source" is a good mechanism to develop programs.
apple is my favorite food.
Football game is not use feet only.
this dress doesn't fit me.
However, this dress is about $ 3183 dollars.^M
GNU is free air not free beer.^M
Her hair is very beauty.^M
I can't finish the test.^M
Oh! The soup taste good.^M
motorcycle is cheap than car.
This window is clear.
the symbol '*' is represented as start.
Oh!     My god!
The gd software is a library for drafting programs.^M
You are the best is mean you are the no. 1.
The world <Happy> is the same with "glad".
I like dog.
google is the best tools for search keyword.
goooooogle yes!
go! go! Let's go.
# I am VBird
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grep进阶操作

搜寻特定字串

[root@localhost ~]# grep -n 'the' regular_express.txt
8:I can't finish the test.^M
12:the symbol '*' is represented as start.
15:You are the best is mean you are the no. 1.
16:The world <Happy> is the same with "glad".
18:google is the best tools for search keyword.
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反向选择

[root@localhost ~]# grep -vn 'the' regular_express.txt
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
4:this dress doesn't fit me.
5:However, this dress is about $ 3183 dollars.^M
6:GNU is free air not free beer.^M
7:Her hair is very beauty.^M
9:Oh! The soup taste good.^M
10:motorcycle is cheap than car.
11:This window is clear.
13:Oh!     My god!
14:The gd software is a library for drafting programs.^M
17:I like dog.
19:goooooogle yes!
20:go! go! Let's go.
21:# I am VBird
22:
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利用中括号 [] 来搜寻集合字节

#搜寻 test 或 taste 这两个单字
[root@localhost ~]# grep -n 't[ae]st' regular_express.txt
8:I can't finish the test.^M
9:Oh! The soup taste good.^M
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#不想要 oo 前面有 g 
[root@localhost ~]# grep -n '[^g]oo' regular_express.txt
2:apple is my favorite food.
3:Football game is not use feet only.
18:google is the best tools for search keyword.
19:goooooogle yes!
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 #oo 前面不想要有小写字节
[root@localhost ~]# grep -n '[^a-z]oo' regular_express.txt
3:Football game is not use feet only.
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当我们在一组集合字节中，如果该字节组是连续的，例如大写英文/小写英文/数字等等， 就可以使用[a-z],[A-Z],[0-9]等方式来书写

也可以使用如下的方法

[root@localhost ~]# grep -n '[^[:lower:]]oo' regular_express.txt
3:Football game is not use feet only.
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行首与行尾字节 ^ $

#让 the 只在行首列出
[root@localhost ~]# grep -n '^the' regular_express.txt
12:the symbol '*' is represented as start.
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#开头是小写字节的那一行就列出
[root@localhost ~]# grep -n '^[a-z]' regular_express.txt
2:apple is my favorite food.
4:this dress doesn't fit me.
10:motorcycle is cheap than car.
12:the symbol '*' is represented as start.
18:google is the best tools for search keyword.
19:goooooogle yes!
20:go! go! Let's go.
#上面的命令也可以用如下的方式来取代
grep -n '^[^a-zA-Z]' regular_express.txt
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^ 符号，在字节集合符号(括号[])之内与之外是不同的！ 在 [] 内代表『反向选择』，在 [] 之外则代表定位在行首的意义

行尾结束为小数点 (.) 的那一行

[root@localhost ~]# grep -n '\.$' regular_express.txt
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
4:this dress doesn't fit me.
10:motorcycle is cheap than car.
11:This window is clear.
12:the symbol '*' is represented as start.
15:You are the best is mean you are the no. 1.
16:The world  is the same with "glad".
17:I like dog.
18:google is the best tools for search keyword.
20:go! go! Let's go.
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任意一个字节 . 与重复字节*

• . (小数点)：代表『一定有一个任意字节』的意思；
• * (星星号)：代表『重复前一个字节， 0 到无穷多次』的意思，为组合形态

#找出 g??d 的字串
[root@localhost ~]# grep -n 'g..d' regular_express.txt
1:"Open Source" is a good mechanism to develop programs.
9:Oh! The soup taste good.^M
16:The world <Happy> is the same with "glad".

#至少两个 o 以上的字串
[root@localhost ~]# grep -n 'ooo*' regular_express.txt
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
9:Oh! The soup taste good.^M
18:google is the best tools for search keyword.
19:goooooogle yes!
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限定连续 RE 字符范围 {}
限制一个范围区间内的重复字节数，使用字符范围{}
注：因为 { 与 } 的符号在 shell 是有特殊意义的，因此， 我们必须要使用转义字符 \ 来让他失去特殊意义才行

#找到两个 o 的字串
[root@localhost ~]# grep -n 'o\{2\}' regular_express.txt
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
9:Oh! The soup taste good.^M
18:google is the best tools for search keyword.
19:goooooogle yes!

#找出 g 后面接 2 到 5 个 o ，然后再接一个 g 的字串
[root@localhost ~]# grep -n 'go\{2,5\}g' regular_express.txt
18:google is the best tools for search keyword.
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基础正规表示法字符汇整 (characters)