diff --git a/Dockerfile b/Dockerfile
index 6b1c35f..c0a461b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -14,6 +14,6 @@ RUN mkdir -p /root/.cheat.sh/log/ \
     && python3 lib/fetch.py fetch-all
 
 # installing server dependencies
-RUN apk add --update --no-cache py3-jinja2 py3-flask
+RUN apk add --update --no-cache py3-jinja2 py3-flask bash
 ENTRYPOINT ["python3"]
 CMD ["bin/srv.py"]
diff --git a/lib/frontend/html.py b/lib/frontend/html.py
index 9c63120..c73e96c 100644
--- a/lib/frontend/html.py
+++ b/lib/frontend/html.py
@@ -84,7 +84,7 @@ def _render_html(query, result, editable, repository_button, topics_list, reques
         data = data.encode('utf-8')
         stdout, stderr = proc.communicate(data)
         if proc.returncode != 0:
-            error(stdout + stderr)
+            error((stdout + stderr).decode('utf-8'))
         return stdout.decode('utf-8')