diff --git a/lib.nix b/lib.nix
index eeaaefc..43b99a6 100644
--- a/lib.nix
+++ b/lib.nix
@@ -105,7 +105,7 @@ in
       script = pkgs.writeShellApplication {
         name = "run-postgres";
         text = ''
-                  if [! -d "${data_dir}"]; then
+                  if [ ! -d "${data_dir}" ]; then
                     echo "Database directory does not exist. Initializing"
                     initdb -D ${data_dir}
                   fi