title: Gnuplot, graph line colour
body: <p>In gnuplot, I draw a graph like below:</p>
  
  <pre><code>gnuplot&gt; set title "Performance analysis" font ", 16"
  gnuplot&gt; set xlabel "Array size" font ", 14"
  gnuplot&gt; set ylabel "Time, milliseconds" font ", 14"
  gnuplot&gt; set xrange [0:25]
  gnuplot&gt; set yrange [0:6300]
  gnuplot&gt; set xtics (5, 9, 11, 13, 15, 17, 19, 21, 23)
  gnuplot&gt; set ytics (88, 296, 433, 835, 1067, 1516, 2592, 3920, 6214)
  gnuplot&gt; set style line 1 linecolor rgb "blue"
  gnuplot&gt; plot "file.dat" using 1:2 title "Graph" with lines
  </code></pre>
  
  <p>it is fine, but the line colour of my graph is still red (default), could you please help me to set it to the blue colour.</p>