title: gnuplot multiple graphs are not interactive
body: <p>I am drawing multiple graphs via a shell script in gnuplot.
  The graphs are drawn correctly, but am not am able to zoom in . Does any variable need to be set?
  Here is the code:</p>
  
  <pre><code>---   for loop of script starts---
      gnuplot -persist &lt;&lt;EOF
              set term x11 1
              set title "IP : $ip Upstream capacity:$UP_CAP kbps"
              plot 'trace-0-dir1.txt' using (\$1-$min1):(\$2-\$1-$mindelay1) with lp
              set term x11 2
              set title "IP: $ip Downstream capacity:$DOWN_CAP kbps"
              plot 'trace-0-dir2.txt' using (\$1-$min2):(\$2-\$1-$mindelay2) with lp
  
      EOF
     ---for loop ends---
  </code></pre>