title: Select 100 random lines from a file with a 1 million which can`t be read into memory
body: <p>Actually, this question was asked one of the interviews, I do not know the exact answer, could you explain in detail ? </p>
  
  <blockquote>
    <p>How would you select 100 random lines from a file with a 1 million
    lines? Can`t read file into memory.</p>
  </blockquote>