Update Dockerfile-debian.template

Co-authored-by: Tianon Gravi <[email protected]>

Author: lfittl

Dockerfile-debian.template

@@ -49,8 +49,9 @@ RUN set -eux; \
 		! grep -q '/usr/share/locale' /etc/dpkg/dpkg.cfg.d/docker; \
 	fi; \
 	apt-get update; apt-get install -y --no-install-recommends locales; rm -rf /var/lib/apt/lists/*; \
-	echo en_US.UTF-8 UTF-8 >> /etc/locale.gen; \
-	locale-gen
+	echo 'en_US.UTF-8 UTF-8' >> /etc/locale.gen; \
+	locale-gen; \
+	locale -a | grep 'en_US.utf8'
 ENV LANG en_US.utf8
 
 RUN set -eux; \