Add more scripts, more cleanup

modules/home/fish/default.nix

@@ -77,6 +77,13 @@ in
         run = ''
           nix run nixpkgs#"$argv[1]" -- $argv[2..-1]
         '';
+        shell = ''
+          set args
+          for arg in $argv
+              set args $args nixpkgs#$arg
+          end
+          nix shell $args
+        '';
       };
     };
   };