title: Dockerfile COPY vs "docker run ... cp"
body: <p>We have a build pipeline that first does a docker build using a dockerfile. That dockerfile has a number of COPY commands. We also have a later step that does a docker run, with 'cp' command, as follows:</p>
  <p>docker run --volume /hostDirA:/containerDirB --workdir /folderB dockerRepo:somebuildnum <strong>cp -R /hostDirC/. /containerDirB</strong></p>
  <p>First, before the main point, it is my understanding that the cp command is copying from one folder to another, both folders on the container. Is that a correct understanding?</p>
  <p>Second, <strong>why would a cp be done in this way in the docker run when COPY is already being done in the docker build via the dockerfile? Are there valid reasons why we wouldn't move this cp to be inside the dockerfile?</strong></p>