anchor.diff:  in with pkgs; buildEnv {
     name = "bergey-env";
     paths= [
  +    ledger3
       gitAndTools.hub
       ripgrep
       notmuch
  
positive.code:     msmtp
      nmap
      haskellPackages.sizes
      ] ++ (if stdenv.isDarwin then [] else [
          gitAndTools.git-annex
          crawl
  
negative.code:     vagrant
      jq
      mr
      htop
      wget
      nix-repl
      nix-prefetch-git
      nox
      rsync
      sloccount
      w3m
      isync # mbsync
      unison
      atool
      aspell
  