title: Using relative paths in gnuplot plot files
body: <p>In a gnuplot instruction file, is it possible to indicate relative paths for the data source files and for the output? The paths must be relative to the gnuplot instruction file path.</p>
  
  <p><strong>Context</strong>
  I have large data files containing between 12 to 50 x-y curves that I process using PHP scripts and gnuplot in order to provide nice graphic views of the data. The views are generated using gnuplot and for each view, I have one .csv file, one gnuplot plotting instruction file and one graphic.</p>
  
  <p>Everything is nicely sorted into folders. Usually, in a folder, the graphics are at the top level, then in a source/subfolder are the .csv and gnuplot files.</p>
  
  <p>Sometimes, I need to slightly change the graphic. So I edit the gnuplot file, and I plot it again by calling gnuplot directly. Everything is fine, until I move the folders elsewhere. Which I do frequently.</p>