I have a continuously updating data file. I want to use Gnuplot to dynamically plot the updating data file, possibly using a window of the last 100 data points.
Is it possible? If so, some pointers are appreciated.
Here's one way you can accomplish it with Gnuplot and some bash scripting:
# An updating data file
while :; do echo $((RANDOM%100)); sleep .1; done > datafile
Initialize Gnuplot with a plot command, and let the other updates come from replot:
(
echo "plot [0:100] [0:100] '< tail -n100 datafile' with lines";
while :; do sleep .4; echo replot; done
) | gnuplot -persist
This makes Gnuplot evaluate tail -n100 datafile every .4 seconds and use the result as the data set. The tail command returns the last 100 lines of datafile.