[SOLVED] how to use grep to match with either whitespace or newline

Issue

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 

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

Solution

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( |$)"

Answered By - Ωmega