Can Windows use a Linux shell instead of cmd?

I was wondering if it is somehow technologically possible for Windows to add some sort of Linux interface? I think it would win over many programmers to develop on Windows.

Any ideas on this?

As well as Cygwin which @ChrisF has mentioned, you can also install a collection of tools ported from Unix that run in a normal Windows environment. Two such examples:

• GnuWin32
• UnxUtils

This enables you to be in a Command Prompt and use commands such as grep, ls, awk and so on. Once you've put the extracted folder in your environment path, the experience of using them is pretty seamless and blends in well:

Take a look at Cygwin. It's

a collection of tools which provide a Linux look and feel environment for Windows.

(taken from their home page).