Dear All,
thank you very much for your help! You guys are great.
I used the solution from wfsp with some modification since $number should be able to be changed. Therefore I took the parts of the solutions of tospo and aartist too. However I gave up the loops with $number because I had to print the title for each plot too. It is readable (imho) in the form of:  my $first = build_command('01', %args);.
I put the complete script here including the gnuplot part.
I knew about the module Chart::Gnuplot. Unfortunately I still cannot download modules on my pc at work. Yes I read Yes, even you can use CPAN - none of the solutions works here. The only one were to copy and paste the code but the module has the XS part so it does not work either. I was not able to persuade my manager as proposed in the article. The command structure in the job can be sometimes more tricky as HoH :-)
Thanks again!
VE

use warnings;
use strict;

my $output = "C:/ .../output.ps";

my $multiplot_title = = qq{set multiplot layout 2, 1 title "The Evalua
+tion X" font "Helvetica-Bold,16"
        set key inside right bottom 
        set xlabel "{/Helvetica=12 Years}"  norotate
        set ylabel "{/Helvetica=12 Results}" rotate by -270 
        }
;

my %args = (
  years => q{[2005.5:2011.5]},
  yscala => q{[:100]},
  sources => [
    {
      source => q{abc},
      color => q{#000080},
      title => q{"{/Helvetica=10 ABC_Stuff}"},
    },
    {
      source => q{def},
      color => q{#800080},
      title => q{"{/Helvetica=10 DEF_Stuff}"},
    },
    {
      source => q{ghi},
      color => q{#008000},
      title => q{"{/Helvetica=10 GHI_Stuff}"},
    },
    {
      source => q{jkl},
      color => q{#000000},
      title => q{"{/Helvetica=10 JKL_Stuff}"},
    },
  ],
  topic => q{this},
  abnormality_border => q{mno},
);

my $first = build_command('01', %args);
my $second = build_command('02', %args);
my $third = build_command('03', %args);
my $fourth = build_command('04', %args);
my $fifth = build_command('05', %args);
my $sixth = build_command('06', %args);

sub build_command {

  my $num = shift;    

  my %args = @_;
  
  
  my $cmd = sprintf(
    qq{plot %s %s }, 
    $args{years}, 
    $args{yscala}
  );
  
  for my $source (@{$args{sources}}){
  
    $cmd .= sprintf(
      qq{"C:/Stuff/%s_%s_%s.csv" title "" with errorbars lt rgb "%s" l
+w 2, }, 
      $source->{source}, 
      $args{topic}, 
      $num,
      $source->{color},
    );

    $cmd .= sprintf(
      qq{"C:/Stuff/%s_%s_%s.csv" title %s with lines lt rgb "%s" lw 3,
+ },
      $source->{source},
      $args{topic},
      $num,
      $source->{title},
      $source->{color},
    );
  }

  $cmd .= sprintf(
    qq{"C:/Stuff/%s_%s_%s.csv" with steps lt 1 lw 5 title "{/Helvetica
+=10 Abnormality Border}" \n\n\n},
    $args{abnormality_border},
    $args{topic},
    $num,
  );
  
  return $cmd;

}

open my $P, "|-", "C:/.../gnuplot" or die;

printflush $P qq[
                
        set terminal postscript color portrait
        set output "$output"
                 
        set termoption enhanced
        set encoding iso_8859_1
        
        ######################################
        $multiplot_title
        set title "The First Indicator"
        $first
        set title "The Second Indicator"
        $second
        unset multiplot
        
        ######################################
        $multiplot_title
        set title "The Third Indicator"
        $third
        set title "The Fourth Indicator"
        $fourth    
        unset multiplot
            
        ######################################
        $multiplot_title
        set title "The Fifth Indicator"
        $fifth
        set title "The Sixth Indicator"
        $sixth    
        unset multiplot
            
        ######################################
        
        
        
]; 

close $P;
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