title: Docker host ip on ubuntu
body: <p>Its baffling how one get host ip address on windows (boot2docker) by just issuing this command: docker-machine ip</p>
  
  <p>But same doesn't work on ubuntu using same command. It always says :
  "docker-machine: command not found"</p>
  
  <p>Any idea on why its not working? or is there different command to find the host ip while running ubuntu as the host machine os and docker host?</p>