title: gnuplot: Create multiple boxplots from different data files on the same output
body: <p>I have a set of files that contain data that I want to produce a set of box plots for in order to compare them. I can get the data into gnuplot, but I don't know the correct format to separate each file into its own plot.</p>
  
  <p>I have tried reading all the required files into a variable, which does work, however when the plot is produced, all the boxplots are on top of each other. I need to get gnuplot to index each plot along one space for each new data file.</p>
  
  <p>For example, this produces the output with overlaying plots:</p>
  
  <pre><code>FILES = system("ls -1 /path/to/files/*")
  
  plot    for [data in FILES] data using (1):($4)  with boxplot notitle
  </code></pre>
  
  <p>I know the X position is being stated explicitly there with the (1), but I'm not sure what to replace it with to get the position to move for each plot. This isn't a problem with other chart types, since they don't have the same field locating them.</p>