Bash scripts run in Powershell. We have hundreds of bash scripts for infrastructure build/deploy/etc. and they are cross-platform. On windows we execute them in Powershell. Powershell's been around for a decade and runs on XP and above (edit: and ships with Windows, I think Win7 and above).
http://en.wikipedia.org/wiki/Windows_PowerShell
http://stackoverflow.com/questions/1098786/run-bash-script-f...