title: How to apply tail command in gnuplot
body: <p>I am defining my two colum data file as below in gnuplot file, <code>plot.gnu</code>.</p>
  
  <pre><code>FILE2='case.out'
  </code></pre>
  
  <p>I want to store the last value of second colum of <code>case.out</code> as <code>Max</code>. I tried as</p>
  
  <pre><code>Max =`(tail -n 2 FILE2 | awk '{print $2}')`
  </code></pre>
  
  <p>But it gives gives me error</p>
  
  <pre><code>Max =
        ^
  "plot.gnu", line 37: constant expression required
  </code></pre>
  
  <p>But if I define exact name of file, <code>case.out</code>, instead writing <code>FILE2</code> in Max command then it works well.</p>
  
  <p>My case.out is something line</p>
  
  <pre><code>3.2853  243.4008
  3.2936  243.6239
  3.3019  243.8089
  3.3103  243.9544
  3.3186  244.0590
  3.3269  244.1221
  3.3353  244.1432
  </code></pre>
  
  <p>and I want the the <code>Max</code> command should store <code>244.1432</code> value.
  i.e</p>
  
  <pre><code>print Max
  </code></pre>
  
  <p>should give  <code>244.1432</code></p>