Skip to content

Latest commit

 

History

History
736 lines (369 loc) · 13.5 KB

di-shi-wu-jie-zheng-ze-biao-da-shi.md

File metadata and controls

736 lines (369 loc) · 13.5 KB
Raw

第1章 正则表达式

用于匹配字符串

1.1 grep命令

grep [OPTIONS] PATTERN [FILE...]

cat >> /etc/bashrc << EOF

alias egrep='egrep --color=auto'

alias grep='grep --color=auto'

EOF

1.2 基础正则表达式（Basic RegEx）与扩展正则表达式（Extended RegEx）

基本正则 grep sed

扩展的正则 egrep sed -r awk

适合linux三剑客

以行为单位处理

cat >>/etc/profile<<EOF

alias egrep='egrep --color=auto'

alias grep='grep --color=auto'

EOF

source /etc/profile

export LC_ALL=C

测试文件

cat >>~/test/oldboy.log<<EOF

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 site is http://www.etiantian.org

my qq num is 49000448.

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

gd

good

god

goood

gooood

oldboy1

EOF

1.3 基础正则(BRE)第一波字符说明

1、 ^word 匹配开头word

2、 word$ 匹配word结尾

3、 ^$ 匹配开头结尾 即空行

[root@oldboy test]# grep "^m" oldboy.log

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

my qq num is 49000448.

my god ,i am not oldbey,but OLDBOY!

[root@oldboy test]# grep "m$" oldboy.log

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

[root@oldboy test]# grep -n "^$" oldboy.log

3:

8:

[root@oldboy36 test]# grep "^m" oldboy.log

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

my qq num is 49000448.

my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -n "^$" oldboy.log

3:

8:

[root@oldboy36 test]# grep "oldboy" oldboy.log

I am oldboy teacher!

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

[root@oldboy36 test]# grep "oldb.y" oldboy.log

I am oldboy teacher!

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

my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep "oldb.y" oldboy.log -o

oldboy

oldboy

oldbey

[root@oldboy36 test]# grep ".$" oldboy.log

I teach linux.

my qq num is 49000448.

not 4900000448.

1.4 基础正则（BRE）第二波字符说明

. 代表且只能代表任意一个字符

转译符号，特殊字符还原本意

\n 表示换行

\n 在 echo sed awk 中使用

* 匹配前面的一个字符0次或多次（任意多次）

.* 匹配任意一个字符任意多次（任意字符串）

^.* 匹配开头任意字符串

[root@oldboy36 test]# grep "^.*o" oldboy.log

I am oldboy teacher!

I like badminton ball ,billiard ball and chinese chess!

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

our site is http://www.etiantian.org

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

说明：如果匹配的内容在一行中有多处，grep会从左到右匹配到最后一个，多多益善

提示：点（.）的特殊含义小结：

1、当前目录

2、使得文件生效相当于source

3、隐藏文件的开头

4、任意一个字符

[root@oldboy36 test]# grep -n "." oldboy.log

2:I teach linux.

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

9:not 4900000448.

[root@oldboy36 test]# grep -n "." oldboy.log

1:I am oldboy teacher!

2:I teach linux.

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

9:not 4900000448.

10:my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -n ".*" oldboy.log

1:I am oldboy teacher!

2:I teach linux.

3:

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

8:

9:not 4900000448.

10:my god ,i am not oldbey,but OLDBOY!

1.5 基础正则（BRE）第三波字符说明

[abc] 匹配a、b、c任意一个字符

[^abc] 匹配非a、非b、非c 任意一个字符

a{n,m} 匹配a这个字符 n到m次

a{n,} 匹配a这个字符至少n次

a{n} 匹配a这个字符n次

a{,m} 匹配a这个字符最多m次

注意： 上面的 是转义 ，但是在 egrep (grep -E) 或 sed -r 或 awk {} 不需要转义

[root@oldboy36 test]# grep -n "[abc]" oldboy.log

1:I am oldboy teacher!

2:I teach linux.

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

10:my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -n "[^abc]" oldboy.log

1:I am oldboy teacher!

2:I teach linux.

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

9:not 4900000448.

10:my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -n "[a-Z0-9]" oldboy.log

1:I am oldboy teacher!

2:I teach linux.

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

9:not 4900000448.

10:my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -n "^[abc]" oldboy.log

[root@oldboy36 test]# grep -n "[^abc]" oldboy.log

1:I am oldboy teacher!

2:I teach linux.

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

9:not 4900000448.

10:my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -n "^[^abc]" oldboy.log

1:I am oldboy teacher!

2:I teach linux.

4:I like badminton ball ,billiard ball and chinese chess!

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

6:our site is http://www.etiantian.org

7:my qq num is 49000448.

9:not 4900000448.

10:my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep "[^a-z]" oldboy.log

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 site is http://www.etiantian.org

my qq num is 49000448.

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep "[^0-9]" oldboy.log

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 site is http://www.etiantian.org

my qq num is 49000448.

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep "[^0-9]" oldboy.log

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 site is http://www.etiantian.org

my qq num is 49000448.

not 4900000448.

my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep -v "[0-9]" oldboy.log

I am oldboy teacher!

I teach linux.

I like badminton ball ,billiard ball and chinese chess!

our site is http://www.etiantian.org

my god ,i am not oldbey,but OLDBOY!

[root@oldboy36 test]# grep "[0-9]" oldboy.log

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

my qq num is 49000448.

not 4900000448.

[root@oldboy36 test]# grep "0{2,3}" oldboy.log

my qq num is 49000448.

not 4900000448.

[root@oldboy36 test]# grep -o "0{2,3}" oldboy.log

000

000

00

[root@oldboy36 test]# grep "0{1,5}" oldboy.log

my qq num is 49000448.

not 4900000448.

[root@oldboy36 test]# grep -o "0{1,5}" oldboy.log

000

00000

[root@oldboy36 test]# egrep "0{1,5}" oldboy.log

my qq num is 49000448.

not 4900000448.

[root@oldboy36 test]# egrep -o "0{1,5}" oldboy.log

000

00000

1.6 扩展的正则表达式

  • 匹配前面一个字符一次或多次

a+ 匹配a这个字符一次或多次

? 匹配前面一个字符0次或1次

a? 匹配a这个字符0次或1次

| 表示或者 用于同时过滤多个

( ) 分组 后向引用

egrep "0+" oldboy.txt

egrep -o "0+" oldboy.txt

egrep -o "[a-z]+" oldboy.txt

egrep "[a-z]+" oldboy.txt

egrep -o "[a-z]+" oldboy.txt

egrep -o "[a-zA-Z]+" oldboy.txt

egrep -o "[a-Z]+" oldboy.txt

[root@oldboy36 test]# egrep "go?d" oldboy.log

my god ,i am not oldbey,but OLDBOY!

gd

god

[root@oldboy36 test]# egrep "go+d" oldboy.log

my god ,i am not oldbey,but OLDBOY!

good

god

goood

gooood

[root@oldboy36 test]# egrep "go*d" oldboy.log

my god ,i am not oldbey,but OLDBOY!

gd

good

god

goood

gooood

[root@oldboy36 test]# egrep "go{0,3}d" oldboy.log

my god ,i am not oldbey,but OLDBOY!

gd

good

god

goood

[root@oldboy36 test]# dumpe2fs /dev/sda1 |grep -i "inode size"

dumpe2fs 1.41.12 (17-May-2010)

Inode size: 128

[root@oldboy36 test]# dumpe2fs /dev/sda1 |grep -i "block size"

dumpe2fs 1.41.12 (17-May-2010)

Block size: 1024

[root@oldboy36 test]# dumpe2fs /dev/sda1 |grep -i "inode count"

dumpe2fs 1.41.12 (17-May-2010)

Inode count: 51200

[root@oldboy36 test]# dumpe2fs /dev/sda1 |grep -i "block count"

dumpe2fs 1.41.12 (17-May-2010)

Block count: 204800

Reserved block count: 10240

[root@oldboy36 ~]# echo "##**##@@##@##*#1@@@@@@@2**@@@**##**" |egrep "[#@*]+"

##**##@@##@##*#1@@@@@@@2**@@@**##**

[root@oldboy36 ~]# echo "##**##@@##@##*#1@@@@@@@2**@@@**##**" |egrep "[#@*]+" -o

##**##@@##@##*#

@@@@@@@

**@@@**##**

[root@oldboy36 test]# egrep "oldb(o|e)y" oldboy.log

I am oldboy teacher!

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

my god ,i am not oldbey,but OLDBOY!

oldboy1

[root@oldboy36 test]# dumpe2fs /dev/sda1 |egrep -i "(inode|block) size"

dumpe2fs 1.41.12 (17-May-2010)

Block size: 1024

Inode size: 128

[root@oldboy36 test]# dumpe2fs /dev/sda1 |egrep -i "(inode|block) count"

dumpe2fs 1.41.12 (17-May-2010)

Inode count: 51200

Block count: 204800

Reserved block count: 10240

[root@oldboy36 test]# dumpe2fs /dev/sda1 |egrep -i "(inode|block) (size|count)"

dumpe2fs 1.41.12 (17-May-2010)

Inode count: 51200

Block count: 204800

Reserved block count: 10240

Block size: 1024

Inode size: 128

1.7 正则表达式特殊符号

[root@oldboy36 test]# echo oldboy1 >> oldboy.log

[root@oldboy36 test]# grep "\boldboy\b" oldboy.log

I am oldboy teacher!

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

[root@oldboy ~]# cat -nA test.txt

 1  asdfsfasfasf$

 2  $                           &lt;=========这个是空行

 3  asdfsf$

 4  sdfasfsa$

 5     $                        &lt;=========这行全是空格

 6  sdfasdfas$

 7  ^I$                         &lt;=========这行是tab键

 8  asdfsad$

[root@oldboy ~]# egrep "^\s*$" test.txt -n

2:

5:

7:

[root@oldboy ~]# egrep "^\s*$" test.txt -nv

1:asdfsfasfasf

3:asdfsf

4:sdfasfsa

6:sdfasdfas

8:asdfsad

[root@oldboy ~]# sed -rn '/^[ \t]*$/{=;p}' test.txt

2

5

7

[root@oldboy ~]# sed -r '/^[ \t]*$/d' test.txt

asdfsfasfasf

asdfsf

sdfasfsa

sdfasdfas

asdfsad

1.8 空行的处理

egrep -v "^$" /oldboy/test.txt

sed '/^$/d' /oldboy/test.txt

awk '/^$/' /oldboy/test.txt

awk '!/^$/' /oldboy/test.txt

1.9 企业案例

[root@oldboy oldboy]# find /root/oldboy -type f|xargs sed -i '/<script language=javascript src=http://%4%66E%78%6F%72%67%2E%70%6F/x.js?google_ad=93x28_ad></script>/d'

[root@oldboy oldboy]# find /root/oldboy -type f|xargs sed -i 's#<script language=javascript src=http://%4%66E%78%6F%72%67%2E%70%6F/x.js?google_ad=93x28_ad></script>##g'

1.10 取出/etc/passwd中的第一列

egrep -o "^[a-zA-Z0-9]+" /etc/passwd

egrep -o "^[^:]+" /etc/passwd

sed -r 's#(^[a-zA-Z0-9#]+).*$#\1#g' /etc/passwd

sed -r 's#(^[^:]+).*$#\1#g' /etc/passwd

1.11 交换/etc/passwd中第一列与最后一列位置

sed -r 's#(^[a-zA-Z0-9#]+)(:.*:)(.*$)#\3\2\1#g' /etc/passwd

sed -r 's#(^[^:]+)(:.*:)(.*$)#\3\2\1#g' /etc/passwd

[root@oldboy ~]# sed -rn 's#(^[^:]+)(:.*:)(.*)#\3\2\1#gp' /etc/passwd|head

/bin/bash:x:0:0:root:/root:root

/sbin/nologin:x:1:1:bin:/bin:bin

/sbin/nologin:x:2:2:daemon:/sbin:daemon

/sbin/nologin:x:3:4:adm:/var/adm:adm

/sbin/nologin:x:4:7:lp:/var/spool/lpd:lp

/bin/sync:x:5:0:sync:/sbin:sync

/sbin/shutdown:x:6:0:shutdown:/sbin:shutdown

/sbin/halt:x:7:0:halt:/sbin:halt

/sbin/nologin:x:8:12:mail:/var/spool/mail:mail

/sbin/nologin:x:10:14:uucp:/var/spool/uucp:uucp