diff --git a/lib.nix b/lib.nix
index 143bab5..8842144 100644
--- a/lib.nix
+++ b/lib.nix
@@ -120,7 +120,7 @@ in
         cp ${configFile} ${data_dir}/postgresql.conf
         if [[ "$POSTGRES_RUN_INITIAL_SCRIPT" == "true" ]]; then
           echo "Running initial script"
-          pg_ctl -D "${data_dir}" -w start -o "-c unix_socket_directories=${data_dir} -c listen_addresses= -p ${lib.toString port}"
+          pg_ctl -D "${data_dir}" -w start -o "-c unix_socket_directories=${data_dir} -c listen_addresses= -p ${builtins.toString port}"
           pg_ctl -D "${data_dir}" -m fast -w stop
         else 
           echo