If using Catalina
sudo mkdir -p /System/Volumes/Data/nix
sudo chown -R `whoami` /System/Volumes/Data/nix
echo "nix\t/System/Volumes/Data/nix" | sudo tee /etc/synthetic.conf
And reboot.
export NIX_IGNORE_SYMLINK_STORE=1
curl https://nixos.org/nix/install | sh
You may also have to do the following:
nix-store --add-fixed --recursive sha256 /Applications/Xcode.app
Use nix shell in pure mode to work on our code.
nix-shell --pure
Follow steps here: https://gist.github.com/wilspi/847b3794a5dda51a62b8bfd4fd968f3b