Interix is a multiuser UNIX environment that operates on computers running Windows. The Interix subsystem and its accompanying utilities provide you with an environment that resembles any other UNIX system. It also includes case-sensitive file names, job control, compilation tools, and the use of over 300 UNIX commands and utilities and shell scripts. Because the Interix subsystem is layered on top of the Windows kernel, it offers true UNIX functionality without any emulation.
A computer running Windows Services for UNIX provides two different command-line environments: the UNIX environment and the Windows environment. Applications run on specific subsystems and in specific environments. When you load the Interix subsystem, you get a UNIX environment; when you run applications on the Windows subsystem, you get a Windows environment.
For example, when you use the Korn shell or C shell that come with Windows Services for UNIX, or any other application that was compiled to use the Interix subsystem, you get a UNIX environment. Among other things, this environment features case-sensitive file names and path names that use the format /usr/examples. For more information on the commands and utilities that are available in the Interix subsystem, see Interix commands and utilities. For more information on files that provide general background information, file format specifications, and configuration details, see Interix subsystem information and file formats.
When you use the command processor cmd.exe you get the Windows environment. Among other things, this environment includes case-insensitive file names, and path names that use the format C:\SFU\usr\examples. For more information about path names in the Interix subsystem and Windows, see Path names in Interix.
The Interix subsystem provides both the tools and the application programming interface (API) libraries for porting applications to run on Windows-based computers. With the Software Development Kit (SDK), which provides a front end for Microsoft Visual C++, you can have a UNIX environment for development, but still have the benefits of the native compiler for Windows. For information about porting applications, see Porting applications to the Interix subsystem.