To run bash within Windows, simply install the Windows Subsystem for Linux by running a command prompt as administrator and typing wsl --install. You will have instant access to bash commands after the installation finishes.
PowerShell inside Linux is a little trickier and distro dependent. Microsoft includes instructions on its website for installing PowerShell on the most popular distros. You may notice that Arch Linux is missing from that list, but it exists as the powershell package in the AUR.