Cygwin

From an availability point of view, Cygwin is all about Windows; this application is available for 32 and 64-bit versions of Microsoft’s Windows operating system.
From a functionality point of view, Cygwin is all about Linux; this application provides access to lots of tools, tools that provide functionality you would expect to get from Linux.

Cygwin plays nice with all 32 and 64-bit Windows editions from XP SP3 onward. The installation process you have to complete to get Cygwin up and running on your PC is presented in the Quick Look video that accompanies this article. You’ll see that installing Cygwin is an effortless task that will not take much of your time.

During the installation process you will be asked to pick the packages that will be installed. They are grouped into several categories: accessibility, admin, audio, database, debug, and more.
During the installation process you will be asked if you want a shortcut on your desktop. This will place a Cygwin Terminal shortcut on your desktop.

You can expect Cygwin to provide access to tools and functionality similar to that offered by a Linux distro. You cannot expect Cygwin to provide a means of running native Linux apps on your Windows-powered PC. To do so, to run a Linux app on Windows, that app must be rebuilt from source. Furthermore, you cannot expect Cygwin to somehow make native Windows apps aware of UNIX functionality. These apps must be rebuilt from source for this.

Cygwin is free software.

I wholeheartedly agree with Cygwin’s motto: “Get that Linux feeling – on Windows.”