diff --git a/nix/validate.nix b/nix/validate.nix
index 13b9224..464fd1e 100644
--- a/nix/validate.nix
+++ b/nix/validate.nix
@@ -12,7 +12,7 @@ writeShellApplication {
 	];
 	text = ''
 		shopt -s globstar
-		find "${PACKER_CONFIG_DIR}" -name '*_linux_amd64' -exec chmod +x '{}' ";"
+		find "''${PACKER_CONFIG_DIR}" -name '*_linux_amd64' -exec chmod +x '{}' ";"
 		packer init sources
 		for vars in distros/**/*.pkrvars.hcl; do
 			packer validate -except=upload "-var-file=''${vars}" sources/