The xgraph program draws a graph on an X display  given data read
from either data files or from standard input if no files are
specified. It can display up to 64  independent data sets using
different colors and/or line styles for each set. It annotates the
graph with a title, axis labels, grid lines or tick marks, grid
labels, and a legend. There are options to control the appearance
of most components of the graph.

Originally written by David Harrison, the code is mostly/completely
unchanged since December 1989, when xgraph-11 was released.
The program relies only upon Xlib calls (and not any specific
toolkit), so it should work on all X systems.
