title: Shell command to Get container id from "docker ps"
body: <p>I am basically looking to achieve this 2 steps:
  1. Run the docker image:
     docker run -p 80:80 some-image-name:25
  2. Now "docker ps" returns whole data about the container but I was looking for just the container ID to
  3. run some test on it.. ex. 
   docker exec -it  /usr/bin/npm run test</p>
  
  <p>So my question is how I can get just the container id from step 2.</p>
  
  <p>Note: I need this flow for my pipeline script in Jenkins.</p>