findstr
This is command line tool in windows( From windows 2000), used to grep string from files. I used it when I reach some codes.
Example:
findstr /I /S /P "main()" * // Search "main()" in all files of this directory and it's sub dir, Case-insensitive
findstr /I /S /P /M main * // get the file name only
For more details, refert to http://www.ss64.com/nt/findstr.html
For others command in Widnows, refert to http://www.ss64.com/nt/