mjhjmtu

I have to plot with Gnuplot the data contained in 3 CSV files.

Commonly, I use the following code to plot from 2 CSV files:

$datablock << EOD
`cat ../Q1a/sim_Q1.csv <(tail -n+8 ../Q1b/sim_Q1.csv | tr '",' ' ' | sort -nk19 )| tail -n+8 | tr '",' ' ' | sort -nk19 > ../Q1a/Q6_ressult.txt`
EOD
set print "|bash -x"
print $datablock
set print

The CSVs are in three different directories.
The data start at row 8, and I must take out the " and , characters, and sort the data by column 19.

I do not know how to extend this code to paste 3 different CSV's doing the same, sort, tail -n+8 and tr commands, and get a final .txt file with the result.

I'm not sure how Gnuplot plays into this specifically, but if you're looking for a way to tail multiple files you can do so simply by passing their names on the command line.

The only gotcha is that tail will separate the outputs with a header for easier human viewing unless you add the -q option:

 -q, --quiet, --silent
 never output headers giving file names

So as far I can see, you can skip the process substitutions and multiple (re)sorts simply do

tail -q -n+8 ../Q1a/sim_Q1.csv ../Q1b/sim_Q1.csv ../Q1c/sim_Q1.csv | tr '",' ' ' | sort -nk19