Question

给出以下文件：

this is some words
and this one too<div>
<html></html>
and more words 123
Caps to begin
ASDFSDFSDF

以下两个命令可以正常运行：

grep -i '[:alpha:]' testfile

给出

this is some words
and this one too<div>
<html></html>
and more words 123
Caps to begin
ASDFSDFSDF

和

grep '[:alpha:]' testfile

给出

this is some words
and this one too<div>
<html></html>
and more words 123
Caps to begin

但

grep '^[:alpha:]' testfile

and this one too<div>
and more words 123

和

grep -i '^[:alpha:]' testfile

and this one too<div>
and more words 123
ASDFSDFSDF

应该确保该行以字母数字开头的插入符号已经搞砸了所有内容。为什么'这是一些单词'行和'开始上限'行没有匹配？这是在Mac Lion上使用bash。

Answer 1

我相信你所寻找的是：

grep '^[[:alpha:]]' testfile
grep -i '^[[:alpha:]]' testfile