title: Access subfolder in dockerfile
body: <p>I'm trying to create a container that installs one of my apps.</p>
  <p>In this application, I have to do a <code>composer install</code> at the root but also in a sub-folder.</p>
  <p>In my dockerfile I do this:</p>
  <pre><code># Switch to non-root 'app' user &amp; install app dependencies
  COPY composer.json composer.lock ./
  RUN chown -R $NON_ROOT_USER:$NON_ROOT_GROUP $LARAVEL_PATH
  USER $NON_ROOT_USER
  # Install composer in base directoru
  RUN composer install --prefer-dist --no-scripts --no-dev --no-autoloader
  # Here I want to go to subfolder
  RUN ls -la
  RUN cd ./web/app/themes/sage
  RUN composer install --prefer-dist --no-scripts --no-dev --no-autoloader
  RUN rm -rf /home/$NON_ROOT_USER/.composer
  </code></pre>
  <p>The problem is, I'm getting the following error:
  <code>can't cd to ./web/app/themes/sage: No such file or directory</code></p>
  <p>However, when I look at the build, I do <code>RUN ls -la</code> and see the correct file architecture with my existing &quot;web&quot; folder.</p>
  <p>How to do ?</p>