diff --git a/ci/build.sh b/ci/build.sh
index f8ab41b..7d5e933 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -1,4 +1,4 @@
-#/usr/bin/env bash
+#!/usr/bin/env bash
 
 set -euo pipefail
 
diff --git a/flake.nix b/flake.nix
index 6be2ff0..f161872 100644
--- a/flake.nix
+++ b/flake.nix
@@ -37,6 +37,7 @@
               dig
               openssl
               caddy
+              shellcheck
             ];
           };
       });