I have a list of variables  {alpha, beta, gamma, delta} and want to plot each of them against a variable called “time” and print the gnuplot to a file using the “.png” option.  How do I rename each file during the loop so that they do not overwrite each other.  I would like to print to files labeled alpha.png, beta.png, gamma.png, and delta.png.

This is the code that I have. The list name is alphabet.  The questions marks are the part of the code I can’t figure out.

loop foreach letter alphabet

         gnuplot $letter time --output= ????????.png

   endloop