gnuplot and shell-script

[leanne_s]

Hi there,

I'm new to this forum and hope you can help me. Several years ago I made some experience with gnuplot, shell-scripting, fortran ... however most of it seems to be lost somewhere in an unreacheable corner of my brain

My problem is the following:

I'm trying to write a shell-script that automatically plots several files into one graph, saves it as eps and converts it to pdf. So far the script is functioning. I also know that I can add files by using the backslash. However, I'm wondering whether there is a way without typing all the file names.

The files are all named the same, only an increasing number at the end is different - like: name_001.txt, name_002.txt ... Is there an option like, let's say, a *-ending. Or can I do it with variables?

Another issue would be: how could I make a script asking me for the file, if for example I only want one file / or asking me how many/which files I want to plot, maybe even which column. I know that somehow it must be done with read ... yet I can't remember and my time is running out (I'm currently in the last semester of my Master Thesis), so I can't read hundreds of pages ... as much as I'd like to - I'm currently really enjoying my time (back) with linux having vista send to nowhere.

I hope you're sympathetic and help me.

Thank you very much!

leanne_s

PS.: I hope my spelling / grammar isn't that bad - unfortunately, English is not my mothertongue

[atreyu]

Yeah, you can use wildcards and ranges, e.g.:

files=$(ls *-00[1-3]*)

would assign the following files to the $files, if they existed:
file-001.txt
file-002.txt
file-003.txt

you can get args from the command line (of bash anyway) by using the $1, $2, $3, etc., e.g.:

#!/bin/bash
arg1=$1
arg2=$2

echo "first arg: $arg1"
echo "seconds arg: $arg2"

and yes, you can use bash's read built-in function to prompt for user input with something like:

read -p "Give me a filename: " myfile
echo "You gave me: $myfile"

[leanne_s]

Hi atreyu,

thank you very much! The last two tips worked immedediately.However, I'm somehow encountering problems with the wildcard option, or rather with plotting my files. It seems that gnuplot recognizes which files I am referring to (tried it with different name-variations), yet when it comes to plotting them, it only plots the first file and then says:

 gnuplot> gnu2.txt' using 2:1 lt 1 pt 13 w p ti 'test''
                 ^
                 line 0: invalid command 
  

(the same when I try gnu_002.txt ...)

I think my plot command is wrong. I tried different variations, too, but none worked; e.g.:

 plot '$FILES' using 2:1 lt 1 pt 13 w p ti 'test' 
  

or

 plot '$FILES' using 2:1 lt 1 pt 13 w p ti 'test', \ 
  

I'd like to have all files in oneplot. By the way, right now my input is the following:

 FILES=$(ls gnu[1-2].txt) 
  

Furthermore, after using wildcards it is not really plotting 'using 2:1'. It plots my y-values but puts them all at the 'zero' of my x-axis, so that I'm only getting a vertical line (or rather vertically aligned points). Not using wildcards, gnuplot plots everything perfectly ...

Any idea? I'm sure, it's my plot command ...

Thank you very much.

leanne_s

[leanne_s]

of course it's no PHP code ...

[atreyu]

as to your wildcard question, i'm not sure why you'd have problems. just do "echo $FILES" in your script, does it echo back your list of files? can you show an example of the script?

as to gnuplot questions, i'm no gnuplot guru, so off the top of my head, i don't know what's wrong. i do have a gnuplot script at home which i can't access right now, so i can back to you later, if nobody else jumps in to help before then.

[leanne_s]

Hi,

here's my code: (it's also echoing the right files - only two in this case as I'm still testing)

#!/bin/bash

FILES=$(ls gnu[1-2].txt)

echo $FILES

gnuplot -persist <<PLOT

set xrange [0:115]
set yrange [0:2.6]
set xtics 0,10,115
set ytics 0,0.2,2.6
set grid xtics ytics


set title "correlation of pressure differences"
set xlabel "{/Symbol D} p (prechamber)"
set ylabel "{/Symbol D} p (testsection)"

set key box outside

#In case for building an eps-file ...
#set terminal postscript enhanced color solid eps 15
#set output "gnu.eps"

plot '$FILES' using 2:1 lt 1 pt 13 w p ti 'test'

#replot

quit
PLOT
#epstopdf gnu.eps

echo "Like it or hate it!"

You MIGHT not be a gnuplot guru, but you already helped me a lot! Right now, I'm also using your other tips not only to read in the names, but also variables/lines/output-file/ranges ... So,I'm really grateful! Also thank you for your fast replies!

[atreyu]

np.

yeah, can't tell what is wrong by looking at the code - must be related to how you're calling gnuplot. will check back in l8r 2nite...

[leanne_s]

Thx!

Just in case you want dummies:

gnu1.txt

      0.020692   0.045158          0
       0.02087   0.047993          0
      0.018751   0.050429          0
      0.036829   0.823043        110
       0.06224   2.412641        162
      0.124688    5.37927        219
      0.285597  14.776962        320
      0.539672   30.24578        422
      1.059578  61.727639        558
      1.865092 110.931687        699
      0.024265   0.061796          0
       0.01728   0.060176          0
      0.022022   0.057191          0

gnu2.txt

      0.022206  0.052979          0
      0.020244  0.052795          0
      0.027779  0.058449          0
       0.03785   0.81835        110
      0.063518  2.346761        160
      0.126946  5.397205        219
      0.288854 14.642722        320
      0.544868 30.088113        420
      1.059355 61.596884        558
        1.8512 110.74555        700
      0.030991  0.064493          0
      0.021839  0.054339          0
      0.024429  0.065023          0

The first column is the pressure difference before and after my test section, the second is the pressure difference of the prechamber (wind tunnel) and normal air pressure and the third is the frequency of the wind turbine [1/min] ... I'm a meteorologist ^^

[atreyu]

okay, for starters, try this dumbed down version:

#!/bin/sh

gnuplot -persist <<PLOT

plot 'gnu1.txt' using 1:2 title 'data A' with lines, \
     'gnu2.txt' using 1:3 title 'data B' with lines

quit
PLOT

it doesn't do everything you want, per your original script, but at least it plots!

[leanne_s]

Thank you, however, I already have a functioning script when typing all files manually (or asking what files, variables ... to plot). The problem is, that I don't want to do the first option as it's neither efficient nor elegant So far, my official script contains 20 of

plot 'gnu1.txt' using 2:1 title 'data A' w p, \
     'gnu2.txt' using 2:1 title 'data B' w p

But there are many more data files to come and I fear that the script might get confusing/cluttered.