anchor.diff:  ENTRYPOINT /bin/bash
   
   ENV RUBY_VERSIONS="2.5.8 2.6.6 2.7.2 3.0.0" \
  +    OLDEST_RUBY_VERSION=2.5.8 \
  +    NEWEST_RUBY_VERSION=3.0.0 \
       DEFAULT_RUBY_VERSION=2.6.6 \
       BUNDLER1_VERSION=1.17.3 \
       BUNDLER2_VERSION=2.2.11 \
  
positive.code:     && ln -s $(which python) /bin/python3
  
  # Install nodenv
  RUN git clone --depth=1 https://github.com/nodenv/nodenv.git ~/.nodenv \
      && cd /root/.nodenv \
      && src/configure \
      && make -C src
  ENV PATH /root/.nodenv/shims:/root/.nodenv/bin:$PATH
  RUN echo 'export PATH="$HOME/.nodenv/bin:$PATH"' >> ~/.bashrc
  RUN echo 'eval "$(nodenv init -)"' >> ~/.bashrc
  RUN mkdir -p "$(nodenv root)"/plugins \
  
negative.code:     && rbenv global ${DEFAULT_RUBY_VERSION}
  
  # Install pyenv
  ENV PYENV_ROOT=/root/.pyenv
  RUN git clone --depth=1 https://github.com/pyenv/pyenv.git $PYENV_ROOT \
      && cd $PYENV_ROOT \
      && src/configure \
      && make -C src
  ENV PATH $PYENV_ROOT/shims:$PYENV_ROOT/bin:$PATH
  RUN echo 'export PYENV_ROOT="$HOME/.pyenv"' >> .bashrc
  RUN echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> .bashrc
  RUN echo 'eval "$(pyenv init -)"' >> ~/.bashrc
  