如何使用grep来匹配空格或换行符 [英] how to use grep to match with either whitespace or newline

问题描述

我想用单词grep一个文件，说AAA，并以空白或换行符结尾。我知道如何单独编写它，如下所示，但在组合它们时存在问题（从输出 VVV AAA 和 AAA VVV ）。

I want to grep a file with a word, say "AAA", and it ends with whitespace or newlines. I know how to write this seperately, as follows, but having problems in combining them (in the sense that it outputs both VVV AAA and AAA VVV).

$echo -e "AAA VVV \nVVV AAA\nBBB" | grep "AAA$" 
>VVV AAA
$echo -e "AAA VVV \nVVV AAA\nBBB" | grep "AAA[[:space:]]" 
>AAA VVV 

我有尝试使用 [] ，但没有成功..

I have tried using [], but without success..

推荐答案

正在查找单词 AAA ，然后在字符串中的任意位置或行尾查找空格，然后使用

If you are looking for word AAA followed by space anywhere in the string, or at the end of line, then use

grep -P "AAA( |$)"

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