diff --git a/Dockerfile b/Dockerfile
index b58ff1e..a354bcb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
 FROM alpine
-RUN apk --no-cache add curl ca-certificates gettext \
+RUN apk --no-cache add curl ca-certificates gettext bash \
   && curl -Ls https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64 > /usr/bin/jq && chmod +x /usr/bin/jq
 ADD bin /opt/resource
diff --git a/bin/in b/bin/in
index ae413f1..e2027c0 100755
--- a/bin/in
+++ b/bin/in
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 . $( dirname "$0" )/common.sh