diff --git a/build-docker.sh b/build-docker.sh
index c969ba2..cb30c52 100755
--- a/build-docker.sh
+++ b/build-docker.sh
@@ -15,6 +15,7 @@ fi
 set -e
 
 if [ -f config ]; then
+	# shellcheck disable=SC1091
 	source config
 fi
 
diff --git a/build.sh b/build.sh
index c41a87f..084d5c6 100755
--- a/build.sh
+++ b/build.sh
@@ -203,8 +203,8 @@ if [[ ! "$FIRST_USER_NAME" =~ ^[a-z][-a-z0-9_]*$ ]]; then
 	exit 1
 fi
 
-if [[ -n "${APT_PROXY}" ]] && ! curl --silent ${APT_PROXY} >/dev/null ; then
-	echo "Could not reach APT_PROXY server:" ${APT_PROXY}
+if [[ -n "${APT_PROXY}" ]] && ! curl --silent "${APT_PROXY}" >/dev/null ; then
+	echo "Could not reach APT_PROXY server: ${APT_PROXY}"
 	exit 1
 fi