Using xgraph to create bar and line graphs

(1) in an xgraph data file list some number of data sets (one per curve)
    A data set contains an ordered pair of X Y coordinates, each point on 
    a separate line.  The name of the data set can be specified by a line
    begining with a double quote.  Here is some sample data for ploting the 
    function f(x) = 2^x and f(x) = x^2:

		"f(x) = 2^x
		1  2
		2  4
		3  8
		4  16
		5  32
		6  64
		7  128 

		"f(x) = x^2
		1  1
		2  4
		3  9
		4  16
		5  25
		6  36
		7  49 


(2) To get xgraph to graph this data do:

	xgraph data_file 

(3) In addition, xgraph has all kinds of command line options for setting
    the scale of the graph, for specifying titiles and lables...

	try:

	xgraph -bar -brw 0.5 data_file
	xgraph -lny data_file 		# specifies logrithmic Y axis
	xgraph -lx 4,6 -ly 16,50 data_file    # zoom into part of the graph

    look at the man page for more options