The bash shell is available for most of the UNIX-like platforms and as the bash package from the Cygwin setup.

If bash isn't already installed or available as a package for your platform, you can get it at: http://www.gnu.org/software/bash/bash.html.

After correct installation, typing at the bash command line prompt:

$ bash --version

should result in something like:

GNU bash, version 3.1.17(6)-release (i686-pc-cygwin)
Copyright (C) 2005 Free Software Foundation, Inc.
      

However, the version string may vary.

The authors don't know of any working Win32 native bash implementation.