2PLOT: plot file - read a plot file and execute subcommands therein

Usage: plot file <file>

reads an input graphics file (default extension: .grf) containing
list data and plot commands and executes the plot commands in the
graphics file. Graphics files cannot be nested. If no output plot
file is open when the file command is executed, and if the first plot
command in the graphics file does not open an output plot file
explicitly, a new Postscript output plot file with the name file.ps
is opened implicitly. An implicitly opened output plot file will be
closed when the end of the graphics file is reached.
