use strict;
use vars qw( $DESTINATION @SOURCES );

$DESTINATION = pop @ARGV;
@SOURCES = @ARGV;

local *DEST;
open DEST, "> $DESTINATION\0"
    or die "Can't overwrite $DESTINATION: $!";
binmode *DEST or die "Can't binmode $DESTINATION: $!";

for my $file_name ( @SOURCES )
{
    local *IN;
    open IN, "< $file_name\0" or die "Can't open $file_name for reading: $!";
    binmode *IN or die "Can't binmode $file_name: $!";

    local $/ = \ 8192;
    while ( my $chunk = <IN> )
    {
        print DEST $chunk
            or die "Can't write to $DESTINATION: $!";
    }

    close IN or warn "Can't close $file_name after reading: $!";
}

close DEST or warn "Can't close $DESTINATION after writing: $!";