Grep中级
...大约 3 分钟
Grep中级
开始结束符号
[root@oldboyedu59 ~]# #在 /etc/services 文件中过滤出包含3306的行
[root@oldboyedu59 ~]# grep '3306' /etc/services
mysql 3306/tcp # MySQL
mysql 3306/udp # MySQL
[root@oldboyedu59 ~]# #在这个文件中找出以ssh开头的行
[root@oldboyedu59 ~]# grep '^ssh' /etc/services
ssh 22/tcp # The Secure Shell (SSH) Protocol
ssh 22/udp # The Secure Shell (SSH) Protocol
ssh 22/sctp # SSH
sshell 614/tcp # SSLshell
sshell 614/udp # SSLshell
ssh-mgmt 17235/tcp # SSH Tectia Manager
ssh-mgmt 17235/udp # SSH Tectia Manager
$符号
[root@oldboyedu59 /oldboy]# grep ' ' oldboy.txt
I am oldboy teacher!
I teach linux.
I like badminton ball ,billiard ball and chinese chess!
my blog is http://oldboy.blog.51cto.com
our size is http://blog.oldboyedu.com
my qq is 49000448
not 4900000448.
my god ,i am not oldbey,but OLDBOY!
[root@oldboyedu59 /oldboy]#
[root@oldboyedu59 /oldboy]# grep 'm$' oldboy.txt
my blog is http://oldboy.blog.51cto.com
our size is http://blog.oldboyedu.com
[root@oldboyedu59 /oldboy]# cat -A 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! $
转义字符
[root@oldboyedu59 /oldboy]# echo -e "oldboy\noldgirl\nalex\nlidao"
oldboy
oldgirl
alex
lidao
[root@oldboyedu59 /oldboy]# echo -e "oldboy\noldgirl\nalex\n\t\t\tlidao"
oldboy
oldgirl
alex
. 和*符号
grep '^.o*' oldboy.txt
^.o*
当表示出现0次 相当于 ^.
当表示出现0次以上 相当于 ^.o ^.oooo ^.oooooooooo
() 小括号 花括号
作用1： 限定多选结构的范围
如：ab(c|d|e)fgh 。
作用2： 标注量词作用的元素
如：ab(cde)+fgh 。小括号里的内容是一个整体。
作用3：捕获组
捕获文本，加括号是为了引用匹配结果。 比如，当我使用([a-zA-Z](\d{2}))((-)\d{3})来进行正则匹配”B33-888”时，匹配情况如下：
group1：B33
group2：33
group3：-888
group4：-
可以看到：匹配的顺序等于左括号出现的顺序。
[] 中括号
中括号 匹配范围。中括号里的内容代表一个范围，可以匹配这个范围内的任意一个元素。
grep '[a-z]' oldboy.txt
grep '[A-Z]' oldboy.txt
grep '[a-zA-Z]' oldboy.txt
grep '[a-z,A-Z]' oldboy.txt
{} 大括号
大括号 匹配次数。匹配在它之前表达式匹配出来的元素出现的次数，{n}出现n次、{n,}匹配最少出现n次、{n,m}匹配最少出现n次，最多出现m次。
练习题:
显示以m或n或o开头的行 以m或n或点结尾的行 显示以m或n或o开头的 并且 以m或n或点结尾的行
显示以m或n或o开头的行
[root@oldboyedu59 /oldboy]#
[root@oldboyedu59 /oldboy]# grep '^[mno]' oldboy.txt
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!
以m或n或点结尾的行
[root@oldboyedu59 /oldboy]#
[root@oldboyedu59 /oldboy]# grep '[mn.]$' oldboy.txt
I teach linux.
not 4900000448.
显示以m或n或o开头的 并且 以m或n或点结尾的行
[root@oldboyedu59 /oldboy]# grep '^[mno].*[mn.]$' oldboy.txt
not 4900000448.
grep '[mn\.]' oldboy.txt
#&&表示并且 命令
grep '^[mno]' oldboy.txt && grep '[mno] $' oldboy.txt
grep '^[mon][mo.]$' /tmp/oldboy
[root@oldboyedu59 /oldboy]# grep '^[mno]' oldboy.txt
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!
[root@oldboyedu59 /oldboy]# grep '^[mno]' oldboy.txt |grep '[mn.]$'
not 4900000448.
找出oldboy.txt 中连续出现的字母（大写或小写）
grep '[^m^n^o]' oldboy.txt
grep '^[mon]|[mo.]$' /tmp/oldboy
扩展正则表达式之 |
[root@oldboyedu59 /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!
\\\\\...???$$$$^^&^
[root@oldboyedu59 /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
扩展正则表达式之 ()
[root@oldboyedu59 /oldboy]# egrep 'oldboy|oldbey' 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!
[root@oldboyedu59 /oldboy]# egrep 'oldb[oe]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!
[root@oldboyedu59 /oldboy]# egrep 'oldbo|ey' 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!
[root@oldboyedu59 /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!
取出文件中正确的身份证号码的行
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
egrep '[0-9X]{18}' id.txt
egrep '[0-9]{17}[0-9X]$' id.txt
基础 扩展 含义 支持命令 grep/sed/awk grep -E/egrep 或 sed -r 或 awk
