How to plot several datasets with titles from one file in Gnuplot?

Question

Assuming I have a file that looks like this:

\"p = 0.1\"
1 1
3 3
4 1


\"p = 0.2\"
1 3
2 2
5 2

Is it possible to make Gnuplot plot these tw

Answer 1

This is Bruce_Warrior's and Ciro Santilli's answers but without the intermediate stats:

# plot.gpi
datafile = ARG1
plot for [i=0:*] datafile index i using 1:2\
with lines title columnheader(1)

The for loop can iterate over all datasets in a file directly. It works in gnuplot 5.0.5 but I'm not sure when for acquired this capability. It is documented in the 5.0 manual but not the 4.6 manual.

Unless the line color should be determined by a third input column consumed by linecolor variable (per Bruce's answer), gnuplot will assign different colors and line styles automatically. In this specific case using 1:2 can also be omitted.

$ gnuplot --version
gnuplot 5.0 patchlevel 5
$ gnuplot --persist -c plot.gpi test.dat

test.dat is

"p = 0.1"
1 1
3 3
4 1


"p = 0.2"
1 3
2 2
5 2