NOTE: Original instructions are here, I have just duplicated here for easy access.

How to install

Do the following from the macOS console:

Install Homebrew. If you dont already have it, run this:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Install Homebrew-Cask so future installations of software via brew is much nicer.

brew tap caskroom/cask

Now you can install PowerShell by running:

brew cask install powershell

You can be sure it is working by running:

pwsh

This should give you the powershell prompt and away you go!

How to upgrade

Run the following from the console:

brew update
brew cask upgrade powershell

That should do it.

How to re-install

If for whatever reason you want to reinstall PowerShell use:

brew cask reinstall powershell

How to remove

If you are nuts and want to remove PowerShell from macOS run:

brew cask uninstall powershell