17个案例带你3分钟搞定Linux正则表达式

正则表达式是一种字符模式，用于在查找过程当中匹配制定的字符。

元字符一般在Linux中分为两类：

Shell元字符，由Linux Shell进行解析；

正则表达式元字符，由vi/grep/sed/awk等文本处理工具进行解析；

正则表达式通常以文本行进行处理，在进行下面实例以前，先为grep命令设置--color参数：

 

$ alias grep='grep --color=auto'

这样每次过滤出来的字符串都会带色彩了。

在开始以前还须要作一件事情，就是建立一个测试用的re-file文件，内容以下：

 

$ cat re-file
I had a lovely time on our little picnic.
Lovers were all around us. It is springtime. Oh
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them?  I can only hope love.
is forever. I live for you. It's hard to get back in the
groove.

文件内容摘录自<<UNIX/SHELL范例精解第四版>>

 

$ cat linux.txt
Linux is a good 
god assdxw bcvnbvbjk
greatttttt  wexcvxc
operaaaating  dhfghfvx
gooodfs awrerdxxhkl
gdsystem awxxxx
glad
good

正则表达式元字符

特殊的元字符