diff --git a/Dockerfile b/Dockerfile
index 24cf449..464d974 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 FROM alpine:3.4
 LABEL author Alfred Gutierrez <alf.g.jr@gmail.com>
 
-ENV NGINX_VERSION 1.13.8
+ENV NGINX_VERSION 1.13.9
 ENV NGINX_RTMP_VERSION 1.2.1
 ENV FFMPEG_VERSION 3.4.2
 
@@ -10,37 +10,56 @@ EXPOSE 80
 
 RUN mkdir -p /opt/data && mkdir /www
 
+# Build dependencies.
 RUN	apk update && apk add	\
-  gcc	binutils-libs binutils build-base	libgcc make pkgconf pkgconfig \
-  openssl openssl-dev ca-certificates pcre \
-  musl-dev libc-dev pcre-dev zlib-dev
+  binutils \
+  binutils-libs \
+  build-base \
+  ca-certificates \
+  gcc \
+  libc-dev \
+  libgcc \
+  make \
+  musl-dev \
+  openssl \
+  openssl-dev \
+  pcre \
+  pcre-dev \
+  pkgconf \
+  pkgconfig \
+  zlib-dev
 
 # Get nginx source.
-RUN cd /tmp && wget http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz \
-  && tar zxf nginx-${NGINX_VERSION}.tar.gz \
-  && rm nginx-${NGINX_VERSION}.tar.gz
+RUN cd /tmp && \
+  wget http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz && \
+  tar zxf nginx-${NGINX_VERSION}.tar.gz && \
+  rm nginx-${NGINX_VERSION}.tar.gz
 
 # Get nginx-rtmp module.
-RUN cd /tmp && wget https://github.com/arut/nginx-rtmp-module/archive/v${NGINX_RTMP_VERSION}.tar.gz \
-  && tar zxf v${NGINX_RTMP_VERSION}.tar.gz && rm v${NGINX_RTMP_VERSION}.tar.gz
+RUN cd /tmp && \
+  wget https://github.com/arut/nginx-rtmp-module/archive/v${NGINX_RTMP_VERSION}.tar.gz && \
+  tar zxf v${NGINX_RTMP_VERSION}.tar.gz && rm v${NGINX_RTMP_VERSION}.tar.gz
 
 # Compile nginx with nginx-rtmp module.
-RUN cd /tmp/nginx-${NGINX_VERSION} \
-  && ./configure \
+RUN cd /tmp/nginx-${NGINX_VERSION} && \
+  ./configure \
   --prefix=/opt/nginx \
   --add-module=/tmp/nginx-rtmp-module-${NGINX_RTMP_VERSION} \
-  --conf-path=/opt/nginx/nginx.conf --error-log-path=/opt/nginx/logs/error.log --http-log-path=/opt/nginx/logs/access.log \
-  --with-debug
-RUN cd /tmp/nginx-${NGINX_VERSION} && make && make install
+  --conf-path=/opt/nginx/nginx.conf \
+  --error-log-path=/opt/nginx/logs/error.log \
+  --http-log-path=/opt/nginx/logs/access.log \
+  --with-debug && \
+  cd /tmp/nginx-${NGINX_VERSION} && make && make install
 
-# ffmpeg dependencies.
+# FFmpeg dependencies.
 RUN apk add --update nasm yasm-dev lame-dev libogg-dev x264-dev libvpx-dev libvorbis-dev x265-dev freetype-dev libass-dev libwebp-dev rtmpdump-dev libtheora-dev opus-dev
 RUN echo http://dl-cdn.alpinelinux.org/alpine/edge/testing >> /etc/apk/repositories
 RUN apk add --update fdk-aac-dev
 
-# Get ffmpeg source.
-RUN cd /tmp/ && wget http://ffmpeg.org/releases/ffmpeg-${FFMPEG_VERSION}.tar.gz \
-  && tar zxf ffmpeg-${FFMPEG_VERSION}.tar.gz && rm ffmpeg-${FFMPEG_VERSION}.tar.gz
+# Get FFmpeg source.
+RUN cd /tmp/ && \
+  wget http://ffmpeg.org/releases/ffmpeg-${FFMPEG_VERSION}.tar.gz && \
+  tar zxf ffmpeg-${FFMPEG_VERSION}.tar.gz && rm ffmpeg-${FFMPEG_VERSION}.tar.gz
 
 # Compile ffmpeg.
 RUN cd /tmp/ffmpeg-${FFMPEG_VERSION} && \
@@ -64,12 +83,13 @@ RUN cd /tmp/ffmpeg-${FFMPEG_VERSION} && \
   --enable-avresample \
   --enable-libfreetype \
   --enable-openssl \
-  --disable-debug \
-  && make && make install && make distclean
+  --disable-debug && \
+  make && make install && make distclean
 
 # Cleanup.
 RUN rm -rf /var/cache/* /tmp/*
 
+# Add NGINX config and static files.
 ADD nginx.conf /opt/nginx/nginx.conf
 ADD static /www/static
 
diff --git a/README.md b/README.md
index a2f4b3e..8e9e9db 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 A Dockerfile installing NGINX, nginx-rtmp-module and FFmpeg from source with
 default settings for HLS live streaming. Built on Alpine Linux.
 
-* Nginx 1.13.8 (compiled from source)
+* Nginx 1.13.9 (compiled from source)
 * nginx-rtmp-module 1.2.1 (compiled from source)
 * ffmpeg 3.4.2 (compiled from source)
 * Default HLS settings (See: [nginx.conf](nginx.conf))