❯ /run/current-system/sw/bin/darwin-rebuild switch -I darwin-config=$HOME/.dotfiles/nix/configuration.nix
building the system configuration...
these derivations will be built:
  /nix/store/i4g7mwp07migk7ab3vwmvidny5p4rdhl-system-applications.drv
  /nix/store/mccpsdka482p6z8p9rxm1flrhb31c5gg-system-path.drv
  /nix/store/iia7ib1nwlkv8222rkpmmw5pmcss9yw4-darwin-system-18.09pre-git.drv
building '/nix/store/i4g7mwp07migk7ab3vwmvidny5p4rdhl-system-applications.drv'...
building '/nix/store/mccpsdka482p6z8p9rxm1flrhb31c5gg-system-path.drv'...
created 0 symlinks in user environment
created 125 symlinks in user environment
building '/nix/store/iia7ib1nwlkv8222rkpmmw5pmcss9yw4-darwin-system-18.09pre-git.drv'...
Password:
warning: Nix search path entry '/Users/nikivi/.nixpkgs/darwin-configuration.nix' does not exist, ignoring
error: file 'darwin-config' was not found in the Nix search path (add it using $NIX_PATH or -I), at (string):1:1
error: Changed <darwin-config> but target does not exist, aborting activation
Create $HOME/.nixpkgs/darwin-configuration.nix or set nix.nixPath:

    nix.nixPath = [ "darwin-config=***" ];