title: How can i reduce the linear fit plot to a certain interval?
body: <p>what i do is to fit two linear function´s to my data. 
  i know how to select the data for the various fitting functions. My problem is that i want the fitted lines only to be plottet in a certain interval. 
  What i did till now:</p>
  
  <pre><code>f(x) = a*x + b; fit [800:1250][-2:8] f(x) 'Daten.txt' u 1:2 via a,b   
  
  g(x) = c*x + d; fit [1258:1650][-2:8] g(x) 'Daten.txt' u 1:2 via c,d                                                                            
  
  plot "Daten.txt" u 1:2 w l, f(x) t title_f(a,b), g(x) t title_g(c,d)                                                            
  </code></pre>
  
  <p>it results in </p>
  
  <p>a picture i´m not allowed to post...</p>
  
  <p>How can i make the green fittin-line only to run from 800-1200 and the blue fitting-line from 1100-end?</p>