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bashgnuplot

plot directly done with gnuplot and input data using a pipe

I have input that I generate directly from Bash (representing y=x^2)

for((i=0;i<10;i++)); do printf "%3d %3d\n" $((i)) $((i*i)); done

I would like to plot these input data with gnuplot and using if possible with a pipe.

I tried to do naively :

for((i=0;i<100;i++)); do printf "%3d %3d\n" $((i)) $((i*i)); done < gnuplot -e "plot u 1:2 w l"

but this can't work because I printf sequentially the values (i,i^2).

I tried to use echo -e (before the redirection "<" of gnuplot) :

echo -e $(for((i=0;i<100;i++)); do printf "%3d %3d\n" $((i)) $((i*i)); done )

on above command (for loop) to find a way to store the 2 entire colums of values and then pass them to gnuplot command, but with this solution, I don't produce 2 columns (I get only a row of data).

Someone could help me to plot the generated data with gnuplot using a pipe (i.e with only one command line)

Thanks for your help

Solution

  • You must pipe the data to gnuplot with for ... | gnuplot -e ... and you must tell gnuplot to read from stdin with plot '-':

    for((i=0;i<100;i++)); do printf "%3d %3d\n" $((i)) $((i*i)); done | gnuplot -e "set terminal pngcairo; set output 'blubb.png'; plot '-' u 1:2 w l"