diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index fac1141..b68aec7 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,46 +1,14 @@
-name: "Build"
-
-permissions:
-  contents: read
-  pages: write
-  id-token: write
-
+name: "Test"
 on:
-  push:
-    branches: [ "main" ]
   pull_request:
-    branches: [ "main" ]
-
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
+  push:
 jobs:
-  build:
+  tests:
     runs-on: ubuntu-latest
-    container:
-      image: "docker://ghcr.io/chrisdone/hell-build:2025-03-04@sha256:ca21e3be038cf1f10fa18306123b4d5f0e2009fe8938cea3afcef7f900bbea71"
-
-      env:
-        # For the ~/.stack root.
-        HOME: /root/
-        STACK_ROOT: /root/.stack
-
-        # This can be both of these, depending on whether it's a PR or
-        # main. GitHub Actions is weird.
-        #
-        # * "GIT_BRANCH=refs/heads/main"
-        # * "GIT_BRANCH=cd/2024-08-28-check-examples"
-        #
-        GIT_BRANCH: ${{ github.head_ref || github.ref }}
-
     steps:
-      - run: |
-          git clone https://github.com/chrisdone/hell /tmp/hell && \
-          cd /tmp/hell && \
-          git checkout $GIT_BRANCH
-      - run: |
-          cd /tmp/hell && stack build --fast
-      - run: |
-          cd /tmp/hell && stack exec hell scripts/check-examples.hell
-      - run: |
-          cd /tmp/hell && HOME=/home/chris/ stack exec hell scripts/check-docs.hell
+    - uses: actions/checkout@v5
+    - uses: cachix/install-nix-action@v31
+      with:
+        github_access_token: ${{ secrets.GITHUB_TOKEN }}
+    - run: nix build
+    - run: nix flake check
diff --git a/flake.nix b/flake.nix
index af7bf2a..2e60ed4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -41,6 +41,15 @@
             pkgs.zlib
           ];
         };
+        checks = {
+          run-script-check = pkgs.runCommand "test-hell-script" {
+            buildInputs = [ app ];
+          } ''
+            hell ${./scripts/check.hell} --dir ${./examples} --dir ${./scripts}
+            touch $out
+          '';
+          build = app;
+        };
         packages = {
           default = app;
           static-arm64 = mkStaticApp pkgsStaticArm64;
diff --git a/scripts/check-examples.hell b/scripts/check-examples.hell
deleted file mode 100644
index 5d07f2b..0000000
--- a/scripts/check-examples.hell
+++ /dev/null
@@ -1,10 +0,0 @@
-main = do
-  examples <- Directory.listDirectory "examples/"
-  let check = \fp -> do
-        Text.putStrLn $ Text.concat ["Checking ", fp]
-        Process.runProcess_ (Process.proc "hell" ["--check", fp])
-  Monad.forM_ examples \example -> do
-    check $ Text.concat ["examples/", example]
-  check "scripts/static-build.hell"
-  check "scripts/install-hell.hell"
-  Text.putStrLn "All OK."
diff --git a/scripts/check.hell b/scripts/check.hell
index b206d6b..3eae609 100644
--- a/scripts/check.hell
+++ b/scripts/check.hell
@@ -1,22 +1,24 @@
 data Opts = Opts {
+  dirs :: [Text],
   compilerStats :: Bool
   }
 
 options =
-  (\compilerStats -> Main.Opts { compilerStats })
-     <$> Options.switch (Flag.long "compiler-stats" <> Flag.help "Pass --compiler-stats in?")
+  (\dirs compilerStats -> Main.Opts { compilerStats, dirs })
+     <$> Alternative.many (Options.strOption (Option.long "dir" <> Option.help "Directory to check"))
+     <*> Options.switch (Flag.long "compiler-stats" <> Flag.help "Pass --compiler-stats in?")
 
 main = do
   opts <- Options.execParser (Options.info (Main.options <**> Options.helper) Options.fullDesc)
   let extra = if Record.get @"compilerStats" opts
                  then ["--compiler-stats"]
                  else []
+  let dirs = Record.get @"dirs" opts
   let list = \dir ->
-        Functor.fmap (List.filter (Text.isSuffixOf ".hell") . List.map (\x -> dir <> x))
+        Functor.fmap (List.filter (Text.isSuffixOf ".hell") . List.map (\x -> dir <> "/" <> x))
           $ Directory.listDirectory dir
-  examples <- list "examples/"
-  scripts <- list "scripts/"
-  Async.pooledForConcurrently (examples <> scripts) \fp -> do
+  examples <- Functor.fmap List.concat $ Monad.mapM list dirs
+  Async.pooledForConcurrently examples \fp -> do
     Text.putStrLn $ Text.concat ["Checking ", fp]
     Process.runProcess_ (Process.proc "hell" (["--check", fp] <> extra))
   Text.putStrLn "All OK."
diff --git a/scripts/readme.md b/scripts/readme.md
deleted file mode 100644
index e6c4b1e..0000000
--- a/scripts/readme.md
+++ /dev/null
@@ -1,62 +0,0 @@
-## Build a distributable
-
-This builds a fully static musl x86-64 Linux binary.
-
-Outside of docker (because it uses Docker):
-
-    hell scripts/static-build.hell
-
-At the end you should have:
-
-    hell-linux-x86-64bit
-
-## Docs
-
-Regenerate docs:
-
-    stack run scripts/gen-docs.hell
-
-Or within the docker container:
-
-    docker exec hell stack run scripts/gen-docs.hell
-
-Example:
-
-    25-03-04 21:41:39.839 $ docker exec hell stack run scripts/gen-docs.hell
-    Generating docs ...
-    Rendering examples/01-hello-world.hell
-    Rendering examples/02-interaction.hell
-    Rendering examples/03-press-any-key.hell
-    Rendering examples/04-writing-files.hell
-    Rendering examples/05-lists.hell
-    Rendering examples/06-polymorphism.hell
-    Rendering examples/07-loops.hell
-    Rendering examples/08-tuples.hell
-    Rendering examples/09-processes.hell
-    Rendering examples/10-current-directory.hell
-    Rendering examples/11-env-vars.hell
-    Rendering examples/12-fib.hell
-    Rendering examples/13-concurrency.hell
-    Rendering examples/14-text.hell
-    Rendering examples/15-type-classes.hell
-    Rendering examples/16-if.hell
-    Rendering examples/17-reuse.hell
-    Rendering examples/18-monads.hell
-    Rendering examples/19-blog-generator.hell
-    Rendering examples/20-dollar.hell
-    Rendering examples/21-json.hell
-    Rendering examples/22-records.hell
-    Rendering examples/23-args.hell
-    Rendering examples/24-exitcode.hell
-    Rendering examples/25-sum-types.hell
-    Rendering examples/26-reference-other-types.hell
-    Rendering examples/27-discussion-64.hell
-    Rendering examples/28-trees.hell
-    Rendering examples/29-temp-files.hell
-    Rendering examples/30-process-handlers.hell
-    Rendering examples/31-open-file-handle.hell
-    Rendering examples/32-optparse.hell
-    Rendering examples/33-null-stream.hell
-    Rendering examples/34-field-puns.hell
-    Rendering examples/35-type-sigs.hell
-    Generated docs.
diff --git a/src/Hell.hs b/src/Hell.hs
index ccde6f7..c2d0e86 100644
--- a/src/Hell.hs
+++ b/src/Hell.hs
@@ -2147,6 +2147,7 @@ polyLits =
 
                -- Alternative operations
                "Alternative.optional" (optional) :: forall (f :: Type -> Type) a. (Alternative f) => f a -> f (Maybe a)
+               "Alternative.many" (many) :: forall (f :: Type -> Type) a. (Alternative f) => f a -> f [a]
 
                -- Monadic operations
                "Monad.mapM_" mapM_ :: forall a (m :: Type -> Type). (Monad m) => (a -> m ()) -> [a] -> m ()