Prettify images description file

Dockerfile

@@ -5,12 +5,12 @@ RUN ln -sf /usr/share/zoneinfo/Etc/UTC /etc/localtime
 
 
 ## Use unicode
-RUN apt update && apt-get -y install locales && \
+RUN apt-get update && apt-get -y install locales && \
     locale-gen en_US.UTF-8 || true
 ENV LANG=en_US.UTF-8
 
 ## Install dependencies
-RUN apt update && apt-get install --no-install-recommends -y \
+RUN apt-get update && apt-get install --no-install-recommends -y \
   openjdk-11-jdk \
   git \
   wget \
@@ -23,7 +23,7 @@ RUN apt update && apt-get install --no-install-recommends -y \
   python
 
 ## Clean dependencies
-RUN apt clean
+RUN apt-get clean
 RUN rm -rf /var/lib/apt/lists/*
 
 ## Install rbenv

desc/desc.sh

@@ -1,25 +1,24 @@
 #!/bin/sh
-
-echo "apt packages:"
-apt list --installed
+echo "## Image environment"
+cat /etc/*-release
 echo
-
-echo "rbenv:"
-rbenv -v
+echo "## Android environment"
+echo "### Android SDKs"
+sdkmanager --list --sdk_root=$ANDROID_HOME |
+    awk '/Installed packages:/{flag=1; next} /Available Packages/{flag=0} flag'
+echo "### Google Cloud SDK"
+gcloud --version
 echo
 
-echo "Default ruby version:"
-ruby -v
+echo "## APT packages"
+dpkg -l
 echo
 
-echo "Installed gems:"
+echo "## Ruby environment"
+echo "### Default ruby version"
+ruby -v
+echo "### rbenv"
+rbenv -v
+echo "### Installed gems:"
 gem list
 echo
-
-echo "gcloud env:"
-gcloud --version
-echo
-
-echo "Android env:"
-sdkmanager --sdk_root=$ANDROID_HOME --list
-echo