diff --git a/lib.nix b/lib.nix
index 29a81fb..6bb6cd6 100644
--- a/lib.nix
+++ b/lib.nix
@@ -109,7 +109,7 @@ in
                     echo "Database directory does not exist. Initializing"
                     ${package}/bin/initdb -D ${data_dir}
                   fi
-          ${package}/bin/postgres -D ${data_dir} --config-file ${configFile}
+          ${package}/bin/postgres -D=${data_dir} --config-file=${configFile}
 
         '';
       };