unix for windows   (link)

http://www.research.att.com/sw/tools/uwin/
The UWIN package provides a mechanism for building and running UNIX applications on Windows 2000, Windows NT, Windows XP, Windows ME, Windows 98, and Windows 95 with few, if any, changes necessary.

The UWIN package contains the following three elements:

* Libraries that provide a UNIX operating system by implementing the UNIX Application Programming Interface (API)
* Include files and development tools such as cc, yacc, lex, and make.
* Korn Shell and over 250 utilities such as ls, sed, cp, stty etc.

The library functions are implemented as functions exported in a DLL (POSIX.DLL). Programs linked with POSIX.DLL run under the WIN32 subsystem instead of the POSIX subsystem. Thus programs can make UNIX library calls or any other WIN32 call as required. A cc command is provided to compile and link programs for UWIN on Windows using traditional UNIX build tools such as make. The cc command is a front end the the underlying compiler that performs the actual compilation and linking. It can be used with the Microsoft Visual C/C++ 5.X compiler, the Visual C/C++ 6.X compiler, the Visual C/C++ 7.X compiler, the Digital Mars compiler C/C++ compiler, the Borland compiler C/C++ compiler, and the Mingw compiler. The GNU compiler and development tools are also available for download with UWIN.