BASH: Plot graph with one line command using gnuplot

This is for a quick visual inspection of your job data output as XY plot. The XY data containing is read from the file data_input.dat

1.00    0.00000
2.00    0.74103
3.00    0.79751
..     ....
..     ....

$ gnuplot
> plot "data_input.dat"

Now a scatter plot will pop up as a window. If you are logged into remote session with ssh, make sure you have forwarded the X. i.e. logged in with -X flag

$ ssh -X yourhost

Change it to line plot by adding ‘with lines’

$ gnuplot
> plot "data_input.dat" with lines

Now for more advanced options:
1. To save the plot as png image, add set terminal png, set output “plot.png”

set terminal png
set output "plot.png"
plot "data_input.dat" with lines

Now the plot will be saved as ‘plot.png’ into working directory. You can open the image from terminal using eog (eye of gnome)

$ eog plot.png

2. To label the X and Y and plot grid, add set ylabel “RMS”, set xlabel “Time” and set grid

set terminal png
set output "plot.png"
set ylabel "RMS"
set xlabel "Time"
set grid
plot "data_input.dat" with lines

3. If you want to plot 1st and 5th column in your data_input.dat, add ‘using 1:5’ in plot command

set terminal png
set output "plot.png"
set ylabel "RMS"
set xlabel "Time"
set grid
plot "data_input.dat" using 1:5 with lines

4. To plot two data series in the same plot and label each line, add next series after a comma

set terminal png
set output "plot.png"
set ylabel "RMS"
set xlabel "Time"
set grid
plot "data_input.dat" using 1:2 with lines title 'data-1', "data_input.dat" using 1:5 with lines title 'data-5'

To plot many series, it’s convenient to use the line continuation character, “\” .

set terminal png
set output "plot.png"
set ylabel "RMS"
set xlabel "Time"
set grid
plot "data_input.dat" using 1:2 with lines title 'data-1', \
"data_input.dat" using 1:3 with lines title 'data-3' \
"data_input.dat" using 1:5 with lines title 'data-5' \

5. Running it from a script, Put all these commands into a script and run if you have to run them several times

#!/usr/bin/gnuplot
reset
set terminal png
set output "plot.png"
set ylabel "RMS"
set xlabel "Time"
set grid
plot "data_input.dat" using 1:2 with lines title 'data-1', \
"data_input.dat" using 1:3 with lines title 'data-3' \
"data_input.dat" using 1:5 with lines title 'data-5' \

matplotlib is another even better option for advanced graph creation
More examples:
1. Gnuplot 4.2 Tutorial
2. Plot your graphs with command line gnuplot
3. Data visualization tools for Linux