nixos-rebuild does flakes now, apparently

build.sh

@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-set -x
-
-BUILD_ARGS=()
-
-if [ -d "../nixpkgs" -a -z "${NO_LOCAL:-}" ]
-then
-    BUILD_ARGS+=("--override-input" "nixpkgs" "../nixpkgs" "--no-write-lock-file")
-fi
-
-sudo nix build --profile /nix/var/nix/profiles/system ".#nixosConfigurations.$(hostname).config.system.build.toplevel" --no-link "${BUILD_ARGS[@]}"

switch.sh

@@ -1,3 +0,0 @@
-#!/usr/bin/env bash
-
-sudo nix shell -vv /nix/var/nix/profiles/system -c switch-to-configuration switch

update.sh

@@ -2,7 +2,7 @@
 set -euo pipefail
 set -x
 
-if [ -d "../nixpkgs" -a -z "${NO_LOCAL:-}" ]
+if [ -z "${NO_LOCAL:-}" ]
 then
     pushd ../nixpkgs
     git fetch --all --prune
@@ -13,4 +13,9 @@ fi
 
 nix flake update --update-input nixpkgs --update-input home-manager --update-input flake-utils
 
-./build.sh && ./switch.sh
+if [ -z "${OVERRIDE:-}" ]
+then
+    sudo nixos-rebuild --flake . switch
+else
+    sudo nixos-rebuild --flake . --override-input nixpkgs ../nixpkgs --no-write-lock-file switch
+fi