grepWin is a simple search and replace tool which can use regular expressions to do its job. This allows to do much more powerful searches and replaces.

當你想知道原始碼中某個關鍵字在資料夾中的哪些檔案出現時(幾百個以上又是多層目錄...)，這個軟體很方便讓您搜尋！

http://stefanstools.sourceforge.net/grepWin.html