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    <div class="moz-cite-prefix">Example in a bash ($) terminal:<br>
      <br>
      username@computername:~/test$ cat test.joint<br>
      #2                              Vol =     421.5088774080<br>
      #  Energy  [eV]     Im_eps_xx          Im_eps_zz<br>
      #<br>
            0.00000     0.25000000E+00     0.00000000E+00<br>
            1.00000     0.50000000E+00     0.50000000E+00<br>
            2.00000     0.75000000E+00     1.00000000E+00<br>
      username@computername:~/test$ cp $WIENROOT/opticplot_lapw
      opticplot2<br>
      username@computername:~/test$ chmod +x opticplot2<br>
      username@computername:~/test$ gedit opticplot2<br>
          Put a comment (#) in front of "rm $tmp1 $tmp2" on line 280 in
      opticplot2 of WIEN2k 14.2<br>
      username@computername:~/test$ sed -n 280p opticplot2<br>
      #    rm $tmp1 $tmp2<br>
      username@computername:~/test$ ./opticplot2<br>
      ...<br>
         File to plot:<br>
      J<br>
      ...<br>
      Which column to plot?  2<br>
      ...<br>
      <img src="cid:part1.04050208.07060003@crimson.ua.edu" alt=""><br>
      Do you want to set ranges? (y/N)N<br>
      Do you want a hardcopy? (y/N)y<br>
      ...<br>
      Specify a filename (default is opticplot.ps)opticplot.ps<br>
      ...<br>
         File to plot:<br>
      q<br>
      username@computername:~/test$ gedit :opt2<br>
          Edit the gnuplot file called :opt2 in text editor [  <a
        class="moz-txt-link-freetext"
href="http://stackoverflow.com/questions/16073232/gnuplot-plotting-a-file-with-4-columns-all-on-y-axis"><a class="moz-txt-link-freetext" href="http://stackoverflow.com/questions/16073232/gnuplot-plotting-a-file-with-4-columns-all-on-y-axis">http://stackoverflow.com/questions/16073232/gnuplot-plotting-a-file-with-4-columns-all-on-y-axis</a></a>
      ]<br>
      username@computername:~/test$ cat :opt2<br>
      set title 'test.joint'<br>
      set style data lines<br>
      set terminal png<br>
      set output "opticplot2.png"<br>
      set xrange [:]<br>
      set yrange [:]<br>
      set xlabel "Energy [eV]"<br>
      set ylabel "Im_eps"<br>
      <br>
      plot ":opt1" using 1:2 title "Im_eps_xx", \<br>
           ":opt1" using 1:3 title "Im_eps_zz"<br>
      username@computername:~/test$ gnuplot :opt2<br>
      <img src="cid:part3.07060002.01010902@crimson.ua.edu" alt=""><br>
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