$/ = undef;
my $string = <$filehandle>;

##</code><code>##

my $old_terminator = $/;
$/ = undef;
my $string = <$filehandle>;
$/ = $old_terminator;

##</code><code>##

my $string;
{
  local $/ = undef;
  $string = <$filehandle>;
}

##</code><code>##

my $string;
{
  local $/;
  $string = <$filehandle>;
}

##</code><code>##

my $string = do {
  local $/;
  <$filehandle>;
}

##</code><code>##

local $/ = <$filehandle>