diff --git a/.envrc b/.envrc
index 3550a30..cc94b51 100644
--- a/.envrc
+++ b/.envrc
@@ -1 +1,2 @@
+nix_direnv_watch_file *.cabal
 use flake
diff --git a/app/Main.hs b/app/Main.hs
index 65ae4a0..ecce4b0 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -1,4 +1,14 @@
 module Main where
 
+import System.PosixCompat.Types
+import System.PosixCompat.Files
+
+getFileSize :: FilePath -> IO FileOffset
+getFileSize = (fileSize <$>) . getFileStatus
+
+getFolderSize :: FilePath -> IO FileOffset
+getFolderSize path = undefined
+
 main :: IO ()
-main = putStrLn "Hello, Haskell!"
+main = do
+  putStrLn "Hello, Haskell!"
diff --git a/flake.nix b/flake.nix
index 85407e1..58b7aa8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,7 +10,7 @@
 
   outputs = { self, nixpkgs, flake-utils }:
     let
-      ghcVer = "ghc962";
+      ghcVer = "ghc945";
       makeHaskellOverlay = overlay: final: prev: {
         haskell = prev.haskell // {
           packages = prev.haskell.packages // {
@@ -52,10 +52,10 @@
               packages = p: [ self.packages.${system}.hcdu ];
               withHoogle = true;
               buildInputs =
-                [ pkgs.docker ] ++
                 (with haskellPackages; [
                   haskell-language-server
                   cabal-install
+                  implicit-hie
                 ]);
               # Change the prompt to show that you are in a devShell
               # shellHook = "export PS1='\\e[1;34mdev > \\e[0m'";
diff --git a/hcdu.cabal b/hcdu.cabal
index 7b6b8ee..18a1bc6 100644
--- a/hcdu.cabal
+++ b/hcdu.cabal
@@ -69,7 +69,9 @@ executable hcdu
         LambdaCase
 
     -- Other library packages from which modules are imported.
-    build-depends:    base ^>=4.18.1.0
+    build-depends:    base ^>=4.17.1.0
+                    , brick >= 1.9
+                    , unix-compat >= 0.7
 
     -- Directories containing source files.
     hs-source-dirs:   app
diff --git a/hie.yaml b/hie.yaml
new file mode 100644
index 0000000..eec6298
--- /dev/null
+++ b/hie.yaml
@@ -0,0 +1,4 @@
+cradle:
+  cabal:
+    - path: "app/Main.hs"
+      component: "hcdu:exe:hcdu"