====== GnuPlot ======

GnuPlot is the ultimate plotting tool and very powerful which has the downside
of being quite hard to use especially for new users. Hopefully this article
clears things up a bit (for me at least).

===== Plotting =====

Probably the most common task performed when using a plotting tool is ...
plotting! Here are a few examples:

Plotting a function:
  gnuplot> plot f(x) = x**2, f(x)

The same as above, but giving the range to plot:
  gnuplot> plot [-5:5] f(x) = x**2, f(x)

Plotting two functions in the same plot:
  gnuplot> plot f(x) = x**2, g(x) = x**3, f(x), g(x)

==== Data Files ====

First, generate some data:
  $ ping nwl.cc | sed -un 's/.*time=\(.*\) ms/\1/p' >/tmp/data

The output looks like this:
<file /tmp/data>
20.8
20.7
23.2
20.2
21.0
19.3
21.2
20.9
22.6
...
</file>

Now plot it:
  gnuplot> plot '/tmp/data' with lines

===== Output To File =====

File output is configured by setting a different terminal than the default
''x11'' for the file type to generate and setting the ''output'' variable for
the filename:

  gnuplot> set terminal png size 800,600
  gnuplot> set output '/tmp/data.png'

Afterwards the output of any ''plot'' command will be written to
///tmp/data.png// in ''png'' format.

Creating PDFs works equvalently, but the ''size'' parameter is interpreted
differently (inches instead of pixels):

  gnuplot> set terminal pdf size 8,6
  gnuplot> set output '/tmp/data.pdf'

But it gets even better, latex output:

  gnuplot> set terminal latex size 8,6
  gnuplot> set output '/tmp/data.tex'

There are various output formats available, one may even chose between
different latex packages to use. For reference, see the output of ''set
terminal'' without further parameters.