Loop structure inside gnuplot?

Question

Is there any way to iteratively retrieve data from multiple files and plot them on the same graph in gnuplot. Suppose I have files like data1.txt, data2.txt......data1000.tx

Answer 1

There sure is (in gnuplot 4.4+):

plot for [i=1:1000] 'data'.i.'.txt' using 1:2 title 'Flow '.i

The variable i can be interpreted as a variable or a string, so you could do something like

plot for [i=1:1000] 'data'.i.'.txt' using 1:($2+i) title 'Flow '.i

if you want to have lines offset from each other.

Type help iteration at the gnuplot command line for more info.

Also be sure to see @DarioP's answer about the do for syntax; that gives you something closer to a traditional for loop.