grep基础正则表达式字符说明：

（1）^word：匹配以word开头的内容；

（2）word$：匹配以word结尾的内容；

（3）^$：表示空行

范例1：匹配以m 开头

[root@oldboy-6test]# grep "^m" oldboy.log

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

my qq num is 49000448

my god,i am not oldboy,but OLDBOY!

范例2：匹配以m 结尾

[root@oldboy-6test]# grep "m$" oldboy.log

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

[root@oldboy-6test]#

范例3：匹配 空行

[root@oldboy-6test]# grep -n "^$" oldboy.log

3:

8:

[root@oldboy-6test]# cat -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,but OLDBOY!

[root@oldboy-6test]#

范例4：排除 空行

[root@oldboy-6test]# grep -v "^$" 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,but OLDBOY!

[root@oldboy-6test]# grep -vn "^$" 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,but OLDBOY!

[root@oldboy-6test]#