use warnings;
use strict;

open(my $fh_1, '>>:raw', 'file1.bin');
open(my $fh_2, '<:raw', 'file2.bin');

my $buffer;
my $bufsize = 32768;
my $copied;

while (1) {
    $copied = read $fh_2, $buffer, $bufsize;
    last if ! $copied;
    print $fh_1 $buffer;
}

use warnings;
use strict;

my @binfiles = qw(
    file1.bin 
    file2.bin 
    file3.bin
);

open(my $fh_out, '>>:raw', 'outfile.bin');

my $buffer;
my $bufsize = 32768;
my $copied;

for my $file (@binfiles) {
    open(my $fh_in, '<:raw', $file);
    READDATA:
    while (1) {
        $copied = read $fh_in, $buffer, $bufsize;
        last READDATA if ! $copied;
        print $fh_out $buffer;
    }
    close($fh_in);
}

print $fh pack "N", $anzahl; # schreibt 4 bytes

print $fh pack "N", length $file01;

#!/usr/bin/perl
# Binary 'cat' für Dateien

use warnings;
use strict;

# print-statements sofort ausgeben
$| = 1;     

my $outfile = '/DeinPfad/DeinDateiname';
my @infiles = qw(
    file1
    file2
    file3
);

open(my $fh_out, '>:raw', $outfile) or die $!;

my $buffer;
my $bufsize = 32768;
my $copied;

for my $file (@infiles) {
    print "Bearbeite $file\n";
    open(my $fh_in, '<:raw', $file) or die $!;
    while ($copied = read $fh_in, $buffer, $bufsize) {
        print $fh_out $buffer;
    }
    close($fh_in) or die $!;
}