From a machine which doesn't have nix on it:
```
./scripts/install_nix.sh
# validate nix and flakes are enabled
nix run nixpkgs#cowsay -- it works!
```
Or from a existing mac machine with nix on it:
```
# Revert nix.conf to it's original state install state
echo "build-users-group = nixbld" | sudo tee /etc/nix/nix.conf > /dev/null
# Run script
./scripts/install_nix.sh
# Check contents have changed
cat /etc/nix/nix.conf
```