title: How to plot line with missing data points in gnuplot
body: <p>Example: </p>
  
  <p><img src="https://i.stack.imgur.com/Wssnw.png" alt="enter image description here"></p>
  
  <p>I want to plot a chart just like above one: a line with some missing data points, that means the line is discontinuous. </p>
  
  <p>How can I do this?</p>