Fix builds for kaniko-users

GoogleContainerTools/kaniko#1246

Author: Phileas Lebada

Dockerfile-alpine.template

@@ -6,12 +6,11 @@ RUN apk add --no-cache \
 		gmp-dev
 
 # skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
+RUN mkdir -p /usr/local/etc; \
+	printf '%s\n' \
+		'install: --no-document' \
+		'update: --no-document' \
+		>> /usr/local/etc/gemrc
 
 ENV LANG C.UTF-8
 ENV RUBY_MAJOR %%VERSION%%
@@ -71,11 +70,11 @@ RUN apk add --no-cache --virtual .ruby-builddeps \
 	\
 # hack in "ENABLE_PATH_CHECK" disabling to suppress:
 #   warning: Insecure world writable dir
-	{ \
+	( \
 		echo '#define ENABLE_PATH_CHECK 0'; \
 		echo; \
 		cat file.c; \
-	} > file.c.new; \
+	) > file.c.new; \
 	mv file.c.new file.c; \
 	\
 	autoconf; \

Dockerfile-debian.template

@@ -4,10 +4,10 @@ SHELL ["/bin/bash", "-eux", "-c"]
 
 # skip installing gem documentation
 RUN mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
+	printf '%s\n' \
+		'install: --no-document' \
+		'update: --no-document' \
+		>> /usr/local/etc/gemrc
 
 ENV LANG C.UTF-8
 ENV RUBY_MAJOR %%VERSION%%
@@ -38,11 +38,11 @@ RUN savedAptMark="$(apt-mark showmanual)"; \
 	\
 # hack in "ENABLE_PATH_CHECK" disabling to suppress:
 #   warning: Insecure world writable dir
-	{ \
+	( \
 		echo '#define ENABLE_PATH_CHECK 0'; \
 		echo; \
 		cat file.c; \
-	} > file.c.new; \
+	) > file.c.new; \
 	mv file.c.new file.c; \
 	\
 	autoconf; \

Dockerfile-slim.template

@@ -17,10 +17,10 @@ RUN apt-get update; \
 
 # skip installing gem documentation
 RUN mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
+	printf '%s\n' \
+		'install: --no-document' \
+		'update: --no-document' \
+		>> /usr/local/etc/gemrc
 
 ENV LANG C.UTF-8
 ENV RUBY_MAJOR %%VERSION%%
@@ -98,7 +98,7 @@ RUN savedAptMark="$(apt-mark showmanual)"; \
 # make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
 	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
 	gem update --system "$RUBYGEMS_VERSION"; \
-	rm -r /root/.gem/; \
+	rm -fr /root/.gem/; \
 # verify we have no "ruby" packages installed
 	if dpkg -l | grep -i 'ruby'; then false; fi; \
 	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \