title: How to Run a Simple Airflow DAG
body: <p>I am totally new to Airflow. I would like to run a simple DAG at a specified date. I'm struggling to make difference between the start date, the execution date, and backfilling. And what is the command to run the DAG?</p>
  
  <p>Here is what I've tried since:</p>
  
  <pre><code>airflow run dag_1 task_1 2017-1-23
  </code></pre>
  
  <p>The first time I ran that command, the task executed correctly, but when I tried again it did not work.</p>
  
  <p>Here is another command I ran:</p>
  
  <pre><code>airflow backfill dag_1 -s 2017-1-23 -e 2017-1-24
  </code></pre>
  
  <p>I don't know what to expect from this command. Will the DAGs execute every day from 23 to 24?</p>
  
  <p>Before running the two commands above, I did this:</p>
  
  <pre><code>airflow initdb
  airflow scheduler 
  airflow webserver -p 8085 --debug &amp;
  </code></pre>
  
  <p>Here is my DAG </p>
  
  <pre><code>from airflow import DAG
  from airflow.operators.bash_operator import BashOperator
  from datetime import datetime, timedelta
  default_args = {
      'owner': 'airflow',
      'depends_on_past': False,
      'start_date': datetime(2017, 1, 23, 12),
      'email': ['airflow@airflow.com'],
      'email_on_failure': False,
      'email_on_retry': False,
      'retries': 1,
      'retry_delay': timedelta(minutes=5),
  }
  
  dag = DAG(
      'dag_1', default_args=default_args, schedule_interval=timedelta(1))
  
  t1 = BashOperator(
      task_id='create_clients',
      bash_command='Rscript /scripts/Cli.r',
      dag=dag)
  
  t2 = BashOperator(
      task_id='create_operation',
      bash_command='Rscript Operation.r',
      retries=3,
      dag=dag)
  
  t2.set_upstream(t1)
  </code></pre>
  
  <p>Screenshot:<a href="https://i.stack.imgur.com/HBhF6.png" rel="noreferrer">Tree View</a></p>
  
  <p><strong>UPDATE</strong></p>
  
  <pre><code>airflow run dag_1 task_1 2017-1-23T10:34
  </code></pre>