Creating a command with sprintf. Is this possible? - gnuplot

Question

I want to plot some data. The data is in several files and the line it is in is not always the same. Therefore I used grep and some other commandline tools to extract the line I want. I read online, that it should be possible with gnuplot to print from a string or from the result of a commandline.
I work in linux.
set terminal pdfcairo enhanced font "Garamond,10" fontscale 1.0 size 9in,9in
set nogrid
set samples 1001
set border 31 linewidth .3
set output "access/accessTimeAcrossFreq.pdf"
set xlabel "freq"
set ylabel "Time [s]"
set key right top
set size square
set autoscale y
set termoption lw 2.5
volts = "0.8"
fins = "111 122 222"
freq = "0.5G 1G 1.5G 2G 2.5G 3G"
metrics = "read1bldeltav read0bldeltav read1senseChange read0senseChange read1latchChange read0latchChange sense1speed sense0speed write1CellFlip write0CellFLip write1CellSwing write0CellSwing write1BLSwing write0BLSwing powerpertime"
runTitle = "abetraryString"
filename(fin, f, volt) = sprintf("../%s_temp27_fin%s_freq%s_vdd%s/accessTimeVolLSA/result.txt", runTitle, fin, f, volt)
data(met, file) = system(sprintf("grep -n '%s' %s | cut -d: -f 2 | awk '{$1=$1};1'", met, file))
com(met, file) = sprintf("< grep -n '%s' %s | cut -d: -f 2 | awk '{$1=$1};1'", met, file)
do for [fin in fins] {
do for [v in volts] {
do for [met in metrics] {
set title sprintf("%s VLSA across Freq, fins %s, %sV, w/o she", met, fin, v)
plot for[i=1:words(freq)] com(met, filename(fin, word(freq, i), v)) using (i):2:xtic(word(freq, i)) notitle with points lc i
}
}
}
So I was wondering if a) I can have a function that returns a string that is a command that is then run by gnuplot
b) Where the error might come from:
line 32: warning: Skipping data file with no valid points
line 32: warning: Skipping data file with no valid points
line 32: warning: Skipping data file with no valid points
line 32: warning: Skipping data file with no valid points
line 32: warning: Skipping data file with no valid points
line 32: warning: Skipping data file with no valid points
line 32: x range is invalid
I thought, maybe I need a linebreak at the end of my one-liner of data. Or because gnuplot always thinks the first line is not data... I don't know.

Answer 1

Today I figured it out. I used prints in the for loop to see what the command returns. Before I posted the question I tried the command in a separate terminal with success. The problem was I just tested it with the first element of metrics. The prints revealed that I forgot the metrics need to be all lower case.
To conclude. Yes, you can put a string via a function together and gnuplot will then run it as I was expecting it. See the use of com(..) in the plot line.
Second. I think the xrange error usually points out that in a plot there are no data points and gnuplot does not like a xrange of 0. To figure this out I used prints. I did a quick search if there is a verbose mode but was not successful, so prints it is.
Maybe someone can take away something like I did.