Full text search of files in a single folder

For example, I have many files in a folder. But I need to search a keyword in all the files, and display where exactly its located in the files.
Any software for this?
Answer #1
http://www.flexiblesystems.com/blog/how-to-search-for-all-files-containing-a-word-or-phrase/
I think the difference in whether Windows search works or not depends on the FILE EXTENSION which contains your search text. For example, if you look for the word "spam", it will be found if it is in a whatever.doc file, or whatever.txt file. However, if you were to rename the file to whatever.xyz, it will no longer find the word.
Here are all the steps I think you need to follow to actually search:
1. Make sure that Windows 7 is actually going to search files with your extension, and it appears that using this list properly is important *whether or not you are looking in an indexed location*!!
a. Hit the start button and type "search" in the search box.
b. Select "Change How Windows Searches"
c. Hit "Advanced"
d. Select the "File Types" tab.
e. Make sure the file extension for the files you want to search in is on the list *and* is set to "Index Properties and File Contents" (yes, pick your jaw up off the floor). I know this appears to be for file indexing, but it does seem to make a difference on whether you find the file in non-indexed locations as well.
f. Say "Ok" and exit all the dialog boxes
Answer #2
a cmd promt and
find /N /I “search” *.txt
will list all the files with the text “search” in them
Answer #3
You did not tell us if binary or text. So all the answered are irrelevant. If their text files, its called regex.