Cygwin is an open source collection of tools that allows Unix or Linux applications to be compiled and run on a Windows operating system from within a Linux-like interface. This capability helps developers to migrate applications from Unix or Linux to Windows-based systems, and makes it easier to support their applications running on the Windows platform. Cygwin includes a dynamic link library (DLL) and a collection of tools. The DLL serves as a Linux emulator, and the tool set provides the Linux-like development environment.
Using Cygwin, developers can more easily provide remote support for applications running on Windows platforms. Because Unix and Linux are open to public input, administrators have contributed a great number of management scripts for these systems over the years, helping to assemble a large collection of available administrative tools. Cygwin makes it possible to use these scripts on computers running Windows, as well. An administrator can log in to a Windows-based computer and fix user problems within a Unix or Linux shell, and can also incorporate Windows command line interface tools into the shell script environment.
The name Cygwin was created from a combination of Cygnus and Windows.