linux 正则匹配小记

1.使用正则匹配文件名

## grep -n '[^\/][a-zA-Z0-9]*[.a-zA-Z0-9][a-zA-Z0-9]*$' regular_express.txt

/etc/init.d/hello.h

/etc/init.d/hehe

2.使用sed提取出网卡IP

（1）

# ifconfig eth0 |grep 'inet addr'

inet addr:192.168.211.129 Bcast:192.168.211.255 Mask:255.255.255.0

（2）

# ifconfig eth0 |grep 'inet addr' | sed 's/^.*addr://g'

192.168.211.129 Bcast:192.168.211.255 Mask:255.255.255.0

（3）

# ifconfig eth0 |grep 'inet addr' | sed 's/^.*addr://g' | sed 's/Bcast.*$//g'

192.168.211.129

3.

(1)过滤'MAN'

# cat /etc/man.config |grep -n 'MAN'

(2)将以#开头的句子后面内容替换为空

# cat /etc/man.config |grep -n 'MAN' | sed 's/#.*$//g'

11:

17:

18:

19:

39:

41:

43:MANPATH /usr/man

44:MANPATH /usr/share/man

45:MANPATH /usr/local/man

46:MANPATH /usr/local/share/man

47:MANPATH /usr/X11R6/man

(3)删除空行

# cat /etc/man.config |grep 'MAN'|sed 's/#.*$//g' | sed '/^$/d'

MANPATH /usr/man

MANPATH /usr/share/man

MANPATH /usr/local/man

MANPATH /usr/local/share/man

MANPATH /usr/X11R6/man