How To Create Chart In Linux (unsing gnuplot)

Read this first

    https://stackoverflow.com/questions/327576/how-do-you-plot-bar-charts-in-gnuplot


You need to create 2 files:-

#===================
#   gnuplot.dat
#===================
0 label       100
1 label2      450
2 "bar label" 75

#===================
#   gnuplot.cmd
#===================
set boxwidth 0.5
set style fill solid
set term svg 
set output "mychart.svg"
plot "gnuplot.dat" using 1:3:xtic(2) with boxes

Now, run this command:-

    gnuplot gnuplot.cmd

This will create the output file

    mychart.svg

To view the chart

    display mychart.svg

Tutorial helps a lot 
    http://www.gnuplot.info/docs/tutorial.pdf