正则表达式符号
标准符号
^ : 以……开头的
[root@lalala /oldboy]# grep '^I' oldboy.txt
I am oldboy teacher!
I teach linux.
I like badminton ball ,billiard ball and chinese chess!
$ 以…… 结尾的
[root@lalala /oldboy]# grep 'txt$' oldboy.txt
oldboy.txt
. 匹配任意一个字符
[root@lalala /oldboy]# grep '.o' oldboy.txt
oldboy.txt
I am oldboy teacher!
I like badminton ball ,billiard ball and chinese chess!
my blog is http://oldboy.blog.51cto.com
our size is http://blog.oldboyedu.com
not 4900000448.
my god ,i am not oldbey,but OLDBOY!
oldboy
- 前一个字符出现0次或0次以上
.* 取前面所有的字符
[root@lalala /oldboy]# grep '.*o' oldboy.txt
oldboy.txt
I am oldboy teacher!
I like badminton ball ,billiard ball and chinese chess!
my blog is http://oldboy.blog.51cto.com
our size is http://blog.oldboyedu.com
not 4900000448.
my god ,i am not oldbey,but OLDBOY!
oldboy
[root@lalala /oldboy]#
\ 转义字符 取消字符的特殊意义
[root@lalala /oldboy]# tr '\n' '\t' <oldboy.txt
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! #12345567 oldboy [root@lalala /oldboy]#
[^] 取反
扩展符号
- 前一个字符连续出现了一次或多次
| 或者
() 括号内的内容为一个整体
{} 匹配多少次
? 前一个字符出现了零到一次
