use strict; 
use warnings;
use Class::CSV;

my $f1 = "/home/Documents/Compare/prtg.csv";
my $f2 = "/home/Documents/Compare/serverliste.csv";
my $outfile = "/home/Documents/Compare/final_result.csv";
my %results = (); 

open FILE1, "$f1" or die "Could not open file:\n";
while(my $line = <FILE1>)
{  
$results{$line}=1;
}
close(FILE1);
 
open FILE2, "$f2" or die "Could not open file:\n";
while(my $line =<FILE2>)
{  
$results{$line}++;
}
close(FILE2);  

open (OUTFILE, ">$outfile") or die "Cannot open $outfile for writing \n";
foreach my $line (keys %results)
{ 
print OUTFILE $line if $results{$line} == 1;
}
close OUTFILE;