Yes there is only one program for Windows PC which have solid GUI and it is essential util for me. I work as a developer and on every computer I've had, first thing install XFind program. It is created in 1997 and till now version is 1.0 and till now works and it is the best. Frequently I need to search some string in a ".cs", ".aspx", ".sct" (Visual FoxPro form code file) or just ".*" and XFind scans all files and show me files and another great thing is that you can look where string is in the file. XFind has also some kind of editor. If it binary file it will show you string finded. Try it and use it forever if you are developer like me.

如果你想要一个GUI, Bare Grep是不错的选择。Gnu grep适合CLI

一个优秀且非常快速的文件搜索工具，Agent Ransack，支持正则表达式搜索。它主要是一个GUI实用程序，但也可以使用命令行界面。

Grep for Windows by GnuWin Project(2014-10-02:它已经过时了，见下面的评论)

如果你必须使用纯Windows，那么除了上面提到的Powershell选项，你还可以使用VBScript，它有很好的RegEx支持。

MS在Technet上还有一个不错的脚本编写区，为管理员提供了大量的示例。

我很惊讶没有人提到FINDSTR。我不是grep poweruser，但findstr做什么我需要它，过滤文件和stdin，与一些基本的正则表达式支持。装有Windows系统的船。(编辑:嗯，有人提到了findstr，我猜是晚了)