diff --git a/images/bench/Dockerfile b/images/bench/Dockerfile
index 291e4256..ec7078e2 100644
--- a/images/bench/Dockerfile
+++ b/images/bench/Dockerfile
@@ -69,6 +69,7 @@ RUN apt-get update \
     xz-utils \
     tk-dev \
     liblzma-dev \
+    file \
     && rm -rf /var/lib/apt/lists/*
 
 RUN sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen \