The line you're likely looking for:

my @data = split(',',$input_buffer);

In context:

#!/usr/bin/perl
use strict;
use warnings;

my @histofeld = ();
open my $input_file, '<', 'test.dat' or die "$!";
while (my $input_buffer = <$input_file>) {
    chomp $input_buffer;
    my @data = split(',',$input_buffer);
    push @histofeld, @data;
}
close $input_file;
[download]