First of Cygwin is not an operating system, but rather an open source "Linux-like environment for Windows" (4.x and up), originally developed by Cygnus Solutions and then acquired by Red Hat. This environment runs most Unix/Linux commands and is a great way to learn Unix CLI and programming although not marketed this way, but rather as a migration tool.

Installing Cygwin

Download the SETUP.EXE file from the Cygwin website. When you start the installation, you will prompted to select a repository to copy the installation packages from. At this point, you can select the default location or any other including local disks. If installing from an on-line repository, you will be prompted for a local sub-directory to copy the packages to, which can be deleted after the installation. By default, the installation process creates the C:\CYGWIN sub-directory where all files including binaries are saved and run from. Since there are no changes written to the Windows Registry, you can delete the C:\CYGWIN sub-directory if you ever decide to get rid of Cygwin.

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