use strict;
use warnings;

use Fcntl qw{:DEFAULT};
use Data::Dump qw{dump};

sysopen my $FILE, 'file', O_RDONLY or die $!;

my ($temp, $buf);

while(1) {
    my $read_cnt = sysread ($FILE, $temp, 1024);
    $buf .= $temp;
    last unless $read_cnt;
}

print dump($buf);