use IO::Termios ();

my $handle = IO::Termios->open('/tmp/fakepty', '4800,8,n,1')
	or die  "IO::Termios->open: $!";
while (<$handle>) { # read the port line-by-line
	chomp;
	print time." <$_>\n";
	# write something to the port
	print {$handle} "Three!\n" if /3/;
}
close $handle;

##</code><code>##

  # connect the fake pty to a process that generates output
$ socat pty,raw,echo=0,link=/tmp/fakepty \
  exec:'perl -e "$|=1;while(1){print q{Foo },$x++,qq{\n};sleep 2}"'

  # connect the fake pty to the current terminal
$ socat pty,raw,echo=0,link=/tmp/fakepty -,icanon=0,min=1

##</code><code>##

use Fcntl qw/:DEFAULT/;
use IO::Termios ();
use IO::Stty ();

sysopen my $fh, '/tmp/fakepty', O_RDWR or die "sysopen: $!";
my $handle = IO::Termios->new($fh) or die "IO::Termios->new: $!";
$handle->set_mode('4800,8,n,1');
IO::Stty::stty($handle, qw/ raw -echo /);

my $tosend = "Hello, World!\n";
$handle->syswrite($tosend)
	== length($tosend) or die "syswrite";

for (1..3) {
	my $toread = 1;
	$handle->sysread(my $in, $toread)
		== $toread or die "sysread";
	print "Read $_: <$in>\n";
}

$handle->close;