diff --git a/shell.nix b/shell.nix
index 8ff87a860..d6bc7b130 100644
--- a/shell.nix
+++ b/shell.nix
@@ -118,8 +118,8 @@ let
 
        cleanup_minio() {
          [[ -n "$minio_pid" ]] && kill $minio_pid
-         [[ -n "$minio_dir" ]] && rm -rvf ''${minio_dir}
-         [[ -n "MINIO_LOGFILE" ]] && rm -rvf ''${MINIO_LOGFILE}
+         [[ -n "''${MINIO_DIR}" ]] && rm -rvf ''${MINIO_DIR}
+         [[ -n "''${MINIO_LOGFILE}" ]] && rm -rvf ''${MINIO_LOGFILE}
        }
 
        MINIO_DIR=$(mktemp -d)