is there a possibility to add ( or perform another operation) in gnuplot
directly with data from different data files ?
An example :
What I would like to do is to add the second column of the file
'test1.dat' and 'test2.dat'
'test1.dat' u 1:2 t "test 1" w l 1,\
'test2.dat' u 1:2 t "test 2" w l 2,\
sum of test1+test2 w l 3
Naturally, the third line is just a synonyme for the operation I would
like to perform.
I belive I have to add the data before plotting, but it would be very
convenient the other way.