ShellJS is a portable (Windows included) implementation of Unix shell commands on top of the Node.js API. You can use it to eliminate your shell script's dependency on Unix while still keeping its familiar and powerful commands. You can also install it globally so you can run it from outside Node projects - say goodbye to those gnarly Bash scripts!
The project is unit-tested and battled-tested in projects like:
PDF.js - Firefox's next-gen PDF reader
Firebug - Firefox's infamous debugger
Yeoman - Web application stack and development tool
Deployd.com - Open source PaaS for quick API backend generation
and many more.