title: CSV - remove rows in which any column is empty
body: <p>I'm playing with the Titanic data set from Kaggle. I'd like to remove any rows from train.csv that have an empty column (I know this isn't the best way to deal with missing data, but this question is interesting to me regardless).</p>
  
  <p>I'd like to do this Unix-type way (using something like awk, sed, or grep), because I'm trying to get better at those tools, but I'm not even sure where to start.</p>
  
  <p>Example of the data:</p>
  
  <pre><code>PassengerId,Survived,Pclass,Name,Sex,Age,SibSp,Parch,Ticket,Fare,Cabin,Embarked
  1,0,3,"Braund, Mr. Owen Harris",male,22,1,0,A/5 21171,7.25,,S
  2,1,1,"Cumings, Mrs. John Bradley (Florence Briggs Thayer)",female,38,1,0,PC 17599,71.2833,C85,C
  3,1,3,"Heikkinen, Miss. Laina",female,26,0,0,STON/O2. 3101282,7.925,,S
  </code></pre>
  
  <p>In the second row, cabin is empty, so I want to remove it from the file.</p>
  
  <p>Note that the fourth column sometimes contains commas, but the column is always contained in double quotes.</p>
  
  <p>ASIDE:</p>
  
  <p>I'd also like to know how to do this for only specific columns, but I can ask that as a separate question if the answer to this question doesn't help me answer that one.</p>