grep command-line with “or” from dos window (gnu grep)

Question

I'm trying to create a .bat file for windows7, using GNU Grep (grep compiled for Win32 target). I'm having trouble with the syntax for an expression that uses the | (or), as the DOS command thinks I'm using it as a pipe/redirect. Here's a sample input foo.txt:

aaa
bbb
ccc
aaa bbb ccc

So I try an easy test:

grep aaa foo.txt

results:

aaa
aaa bbb ccc

So far, so good. But I really need to extract aaa OR bbb, so I use this expression: (aaa|bbb) ex:

grep (aaa|bbb)

gives me:

'bbb)' is not recognized as an internal or external command,
operable program or batch file.

I've tried various quotes, but haven't hit the right combination yet. I need to protect the string from the DOS interpreter, yet have it still be useful to grep. I read the man page and the web documentation, and nothing seemed to fit what I'm trying to do.

Does anyone know how to get this done? thanks.

Answer 1

Need quotes and escaped the pipe with \\ :

grep "aaa\|bbb" foo.txt

---

$ cat foo.txt
aaa
bbb
ccc
aaa bbb ccc

$ grep "aaa\|bbb" foo.txt
aaa
bbb
aaa bbb ccc