詳解基于Linux下正則表達(dá)式（基本正則和擴(kuò)展正則命令使用實(shí)例）

[root@service99 ~]# mkdir /opt/regular
[root@service99 ~]# cd /opt/regular
[root@service99 regular]# pwd
/opt/regular
[root@service99 regular]# cp /etc/passwd temp_passwd

//grep --color 主要是可以將匹配到的文本高亮顯示，這樣便于觀察效果
[root@service99 regular]# grep --color "root" temp_passwd 
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

[root@service99 regular]# ifconfig eth1 | grep --color "add"
eth1   Link encap:Ethernet HWaddr 54:52:01:01:99:02 
     inet addr:192.168.2.99 Bcast:192.168.2.255 Mask:255.255.255.0
     inet6 addr: fe80::5652:1ff:fe01:9902/64 Scope:Link

[root@service99 regular]# echo "This is line number 1" | grep --color "ber 1"
This is line number 1

[root@service99 regular]# echo "This cat is $4.99" //雙引號(hào)不會(huì)屏蔽特殊符號(hào)，所以系統(tǒng)會(huì)讀取變量4.99的值，然而當(dāng)前系統(tǒng)并沒(méi)有該變量，就顯示為空  
This cat is .99
[root@service99 regular]# echo "This cat is \$4.99"  //使用"\"轉(zhuǎn)義$
This cat is $4.99
[root@service99 regular]# echo 'This cat is \$4.99'  //單引號(hào)屏蔽元字符$
This cat is \$4.99
[root@service99 regular]# echo 'This cat is $4.99' 
This cat is $4.99
[root@service99 regular]# cat price.txt 
This price is $4.99
hello,world!
$5.00
#$#$
This is "\".
[root@service99 regular]# grep --color '\\' price.txt 
This is "\".

[root@service99 regular]# grep --color '^h' price.txt  //以字母h開(kāi)頭的行
hello,world!
[root@service99 regular]# grep --color '^$' price.txt //無(wú)輸出結(jié)果，由于沒(méi)有屏蔽特殊含義
[root@service99 regular]# grep --color '^\$' price.txt   //以$符號(hào)開(kāi)頭的行
$5.00
[root@service99 regular]# echo "This is ^ test. " >> price.txt 
[root@service99 regular]# cat price.txt 
This price is $4.99
hello,world!
$5.00
#$#$
This is "\".
This is ^ test. 
[root@service99 regular]# grep --color '^' price.txt //直接使用會(huì)顯示所有的內(nèi)容
This price is $4.99
hello,world!
$5.00
#$#$
This is "\".
This is ^ test. 
[root@service99 regular]# grep --color '\^' price.txt //單獨(dú)使用，并在最前面時(shí)需要屏蔽
This is ^ test. 
[root@service99 regular]# grep --color 'is ^' price.txt //符號(hào)不在最前面時(shí)，無(wú)需屏蔽，直接使用即可
This is ^ test. 

[root@service99 regular]# grep --color '\.$' price.txt //“.”在正則表達(dá)式中也有特殊含義，請(qǐng)屏蔽，具體的請(qǐng)往下看
This is "\".
[root@service99 regular]# grep --color '\. $' price.txt //由于我在輸入的時(shí)候，多加了一個(gè)空格，所以各位需要慎重和小心
This is ^ test.           //在正則表達(dá)式中，空格作為字符計(jì)。
[root@service99 regular]# grep --color '0$' price.txt 
$5.00
[root@service99 regular]# grep --color '9$' price.txt 
This price is $4.99

[root@service99 regular]# cat -n /etc/vsftpd/vsftpd.conf | wc -l
121
[root@service99 regular]# grep -vE '^#|^$' /etc/vsftpd/vsftpd.conf  //v表示反選，E表示支持?jǐn)U展正則“|”是擴(kuò)展正則的符號(hào)，往下看，后面有
anonymous_enable=YES
local_enable=YES
write_enable=YES
local_umask=022
anon_upload_enable=YES
anon_mkdir_write_enable=YES
anon_other_write_enable=YES
anon_umask=022
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
xferlog_std_format=YES
listen=YES
pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES

[root@service99 regular]# grep --color "12345\{0,1\}" price.txt 
1234556
[root@service99 regular]# grep --color "12345\{0,2\}" price.txt 
1234556

[root@service99 regular]# grep --color ".s" price.txt 
This price is $4.99
This is "\".
This is ^ test. 
[root@service99 regular]# grep --color ".or" price.txt 
hello,world!

[root@service99 regular]# grep --color "[abcdsxyz]" price.txt 
This price is $4.99
hello,world!
This is "\".
This is ^ test. 
[root@service99 regular]# grep --color "[sxyz]" price.txt 
This price is $4.99
This is "\".
This is ^ test. 
[root@service99 regular]# grep --color "[abcd]" price.txt 
This price is $4.99
hello,world!
[root@service99 regular]# grep --color "Th[ais]" price.txt //Th 后的第一個(gè)字符在【ais】中匹配的
This price is $4.99
This is "\".
This is ^ test. 
[root@service99 regular]# grep -i --color "th[ais]" price.txt //-i 表示不區(qū)分大小寫(xiě)
This price is $4.99
This is "\".
This is ^ test. 

[root@service99 regular]# echo "Yes" | grep --color "[yY]es"  []內(nèi)字符順序沒(méi)有影響
Yes
[root@service99 regular]# echo "yes" | grep --color "[Yy]es"
yes

[root@service99 regular]# echo "Yes/no" | grep "[Yy][Ee]"
Yes/no
[root@service99 regular]# echo "Yes/no" | grep "[Yy].*[Nn]" //*在正則表達(dá)式中的用法，請(qǐng)往下看
Yes/no

[root@service99 regular]# echo "My phone number is 123456987" | grep --color "is [1234]"
My phone number is 123456987
[root@service99 regular]# echo "This is Phone1" | grep --color "e[1234]"
This is Phone1
[root@service99 regular]# echo "This is Phone1" | grep --color "[1]"
This is Phone1

[root@service99 regular]# echo "regular" | grep --color "r[ea]g[ua]l[ao]"
regular

[root@service99 regular]# cat price.txt 
This price is $4.99
hello,world!
$5.00
#$#$
This is "\".
this is ^ test. 
cat
car
[root@service99 regular]# sed -n '/[^t]his/p' price.txt 
This price is $4.99
This is "\".
[root@service99 regular]# grep --color "[^t]his" price.txt 
This price is $4.99
This is "\".
[root@service99 regular]# grep --color "ca[tr]" price.txt 
cat
car
[root@service99 regular]# grep --color "ca[^r]" price.txt 
cat

[root@service99 regular]# cat price.txt 
This price is $4.99
hello,world!
$5.00
#$#$
This is "\".
this is ^ test. 
cat
car
1234556
911
11806
[root@service99 regular]# egrep --color '[a-z]' price.txt 
This price is $4.99
hello,world!
This is "\".
this is ^ test. 
cat
car
[root@service99 regular]# egrep --color '[A-Z]' price.txt 
This price is $4.99
This is "\".
[root@service99 regular]# grep --color "[0-9]" price.txt 
This price is $4.99
$5.00
1234556
911
11806

[root@service99 regular]# sed -n '/^[^a-Z]/p' price.txt 
$5.00
#$#$
1234556
911
11806
[root@service99 regular]# grep --color "^[^a-Z]" price.txt 
$5.00
#$#$
1234556
911
11806
[root@service99 regular]# echo $LANG  //在使用 [a-Z]時(shí)，注意LANG環(huán)境變量的值，該值若是進(jìn)行修改的話，要注意修改的值的合法性
zh_CN.UTF-8 
[root@service99 regular]# LANG=en_US.UTF-8

[root@service99 regular]# cat test.info 
goole
go go go
come on
goooooooooo
[root@service99 regular]# grep --color "o*" test.info 
goole
go go go
come on
goooooooooo
[root@service99 regular]# grep --color "go*" test.info 
goole
go go go
goooooooooo
[root@service99 regular]# grep --color "w.*d" price.txt   //經(jīng)常與.一起使用
hello,world!

[root@service99 regular]# egrep --color "91?" price.txt 
This price is $4.99
911

[root@service99 regular]# egrep --color "9+" price.txt 
This price is $4.99
911
[root@service99 regular]# egrep --color "1+" price.txt 
1234556
911
11806

[root@service99 regular]# echo "This is test,test is file." | egrep --color "test{0,1}"
This is test,test is file.
[root@service99 regular]# echo "This is test,test is file." | egrep --color "is{1,2}"
This is test,test is file.

grep --color "the" regular_express.txt 

grep --color -vn "the" regular_express.txt 

grep --color -in "the" regular_express.txt 

grep --color -En 'test|taste' regular_express.txt 
grep --color -i "t[ae]ste\{0,1\}" 1.txt 

grep --color "oo" regular_express.txt 

grep --color [^g]"oo" regular_express.txt 
grep --color "[^g]oo" regular_express.txt 

egrep --color "[^a-z]oo" regular_express.txt 

egrep --color [0-9] regular_express.txt 

egrep --color ^the regular_express.txt 

egrep --color ^[a-z] regular_express.txt 

egrep --color ^[^a-Z] regular_express.txt 

egrep --color $"\." regular_express.txt 

egrep --color "^$" regular_express.txt 

egrep --color "g..d" regular_express.txt 

egrep --color "ooo*" regular_express.txt 
egrep --color o\{2,\} regular_express.txt 

egrep --color go\{1,\}g regular_express.txt 

egrep --color [0-9] regular_express.txt 

egrep --color "oo" regular_express.txt 

egrep --color go\{2,5\}g regular_express.txt 

egrep --color go\{2,\} regular_express.txt