diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index 02ec4b0..1324ee6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 /builds
 /ghidra/projects/**/*.lock*
 /mars-db.conf
+/.direnv
diff --git a/flake.nix b/flake.nix
index a36412a..c579a53 100644
--- a/flake.nix
+++ b/flake.nix
@@ -95,26 +95,49 @@ rec {
         buildDebug = mkBuildScript "Debug";
         buildRelease = mkBuildScript "Release";
 
-        # Use this to specify commands that should be ran after entering fish shell
-        initProjectShell = pkgs.writers.writeFish "init-shell.fish" ''
-          echo "Entering \"${description}\" environment..."
-
-          # Determine the project root, used e.g. in cmake scripts
-          set -g -x FLAKE_PROJECT_ROOT (git rev-parse --show-toplevel)
-
-          abbr -a fail "perl ./scripts/menu.pl"
+        # Add project-local fish abbrs here
+        abbrs = {
+          fail = "perl ./scripts/menu.pl";
 
           # C/C++:
-          # abbr -a cmake-debug "${cmakeDebug}"
-          # abbr -a cmake-release "${cmakeRelease}"
-          # abbr -a build-debug "${buildDebug}"
-          # abbr -a build-release "${buildRelease}"
+          # cmake-debug = "${cmakeDebug}";
+          # cmake-release = "${cmakeRelease}";
+          # build-debug = "${buildDebug}";
+          # build-release = "${buildRelease}";
+        };
+
+        eraseAbbr = name: value: ''abbr --erase ${name} 2>/dev/null'';
+        createAbbr = name: value: ''abbr -a ${name} "${value}"'';
+
+        # This will be sourced by the global fish config if INIT_PROJECT_SHELL gets unset
+        unloadProjectShell = pkgs.writers.writeFish "unload-shell.fish" ''
+          echo "Unloading \"${description}\" environment..."
+
+          ${builtins.concatStringsSep "\n" (lib.mapAttrsToList eraseAbbr abbrs)}
+        '';
+
+        # This will be sourced by the global fish config if INIT_PROJECT_SHELL gets set
+        initProjectShell = pkgs.writers.writeFish "init-shell.fish" ''
+          # Unload just in case, to not have redefinition errors
+          source ${unloadProjectShell}
+
+          echo "Sourcing \"${description}\" environment..."
+
+          ${builtins.concatStringsSep "\n" (lib.mapAttrsToList createAbbr abbrs)}
         '';
       in
         builtins.concatStringsSep "\n" [
           # Launch into pure fish shell
           ''
-            exec "$(type -p fish)" -C "source ${initProjectShell} && abbr -a menu '${pkgs.bat}/bin/bat "${initProjectShell}"'"
+            # Can't do the "exec" with nix-direnv
+            # - The "exec fish" would call direnv again => Infinite loop
+            # - The shellHook is Bash/POSIX, so fish syntax doesn't work
+            # exec "$(type -p fish)" -C "source ${initProjectShell} && abbr -a menu '${pkgs.bat}/bin/bat "${initProjectShell}"'"
+
+            # Determine the project root, used e.g. in cmake scripts
+            export FLAKE_PROJECT_ROOT="$(git rev-parse --show-toplevel)"
+            export INIT_PROJECT_SHELL="${initProjectShell}"
+            export UNLOAD_PROJECT_SHELL="${unloadProjectShell}"
           ''
         ];