#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

say $$;
sleep 10;

my $file = shift;
open my $FH, '<', $file or die $!;

my $string;

{ local $/; $string = <$FH> };
say length $string;
sleep 1;

undef $string;

seek $FH, 0, 0;
$string = do { local $/; <$FH> };
say length $string;