Use gnuplot command without prompt

Question

To use the Gnuplot (On linux Ubuntu 16.04) command directly by specifying arguments without using the its prompt, I enter this for example :

gnuplot -e "filename='DataFile.txt'" SettingsFile

Where SettingsFile looks like this :

plot filename with lines
set title "Total Packets consumption"
set xlabel "Time"
set ylabel "Packets"
set datafile separator ","
pause -1

And the DataFile.txt looks like this :

Packets, Time(in seconds) :

First question :

Is there a way to set into that SettingsFile a png OutputFile ? So I can enter it as an argument to the Gnuplot command just as I did with the DataFile. (I want to use it this way, because I want to invoke it from an external code)

I want to achieve something like this :

gnuplot -e "filename='DataFile.txt'" SettingsFile OutputFile.png

Second question :

The screen output that I get from Gnuplot shows the xtics differently than expected :

Notice also that the axis titles are not shown !

Now if I try to resize the window I get this :

The graph gets bizarrely flipped, with the titles set and the tics being updated as desired.

How should I fix these two problems, first mentioning an output file in the SettingsFile, and second the xtics not being showed properly and third this strange behavior in the screen output ?

I would ask the second question in a different post. Also, which version of gnuplot and which terminal (wxt, qt, x11) are you using? Notice that set datafile separator "," should go BEFORE the plot command (the same for the xlabel, ylabel, and title commands). For the first question, try passing command-line arguments to gnuplot — vagoberto
@kebs : linux tag used, I updated my question with full OS info. — AymenDaoudi
@vagoberto You may be right concerning splitting the post into to questions, but... however. I use qt gnuplot, thx for the link, I'll recheck it. — AymenDaoudi

vagoberto vagoberto · Accepted Answer · 2017-01-22T22:06:43

Several commands can be added to gnuplot -e through semicolons, for example:

gnuplot -p -e 'filename="data.txt"; fileout="image.png"' SettingsFile

Your SettingsFile should already have a line configuring the terminal type:

set terminal png
set output fileout

set title "Total Packets consumption"
set xlabel "Time"
set ylabel "Packets"
set datafile separator ","

plot filename using 2:1 with lines

If you want more control over your code, try with this script (gnuplot 5.0+):

filename=(ARGC>0 ? ARG1 : 'DataFile.txt' )  # By default filename=DataFile.txt
                                            # If called with one argument (ARGC=1)
                                            # then `filename=ARG1`

if(ARGC>1){
  # if called with two arguments (ARGC=2), then configure a png output
  set terminal png
  set output ARG2
}

set title "Total Packets consumption"
set xlabel "Time"
set ylabel "Packets"
set datafile separator ","

# the plot command ALWAYS at the end of the script after the settings
plot filename using 2:1 with lines

If you want to plot 'DataFile.txt' (by default) interactively:
```
gnuplot -p SettingsFile
```
If you want to plot another file, e.g. AnotherData.txt:
```
gnuplot -p -c SettingsFile AnotherData.txt
```

If you want to plot another file and save it as PNG:

gnuplot -p -c SettingsFile AnotherData.txt Output.png

The -p argument lets plot windows survive after main gnuplot program exits. Thw -c argument load script using gnuplot's "call" mechanism and pass it the remainder of the command line as arguments. See How to pass command line argument to gnuplot?

Notice that your script plots the datafile first, and THEN configure the labels, title and datafile separator. That is why you see weird tics.

Use gnuplot command without prompt

1 Answers