title: How to install airflow?
body: <p>I seem to be doing sth. wrong.</p>
  
  <p><a href="https://pythonhosted.org/airflow/start.html" rel="noreferrer">https://pythonhosted.org/airflow/start.html</a></p>
  
  <pre><code>$ export AIRFLOW_HOME=~/airflow
  $ pip install apache-airflow
  Requirement already satisfied
  $ airflow initdb
  airflow: Command not found 
  </code></pre>
  
  <blockquote>
    <p>python --version<br>
    Python 2.7.10</p>
  </blockquote>
  
  <p>It's weird - the installation seemed to have worked fine (with some warnings - nothing serious) saying: airflow, flask, etc. successfully installed. But even after restarting the PC (Ubuntu 15.10) airflow seems not to be a command.</p>