Launch a subprocess in a pseudo terminal (pty), and interact with both the

process and its pty.

Sometimes, piping stdin and stdout is not enough. There might be a password

prompt that doesn't read from stdin, output that changes when it's going to a

pipe rather than a terminal, or curses-style interfaces that rely on a terminal.

If you need to automate these things, running the process in a pseudo terminal

(pty) is the answer.

Interface::

p = PtyProcessUnicode.spawn(['python'])

p.read(20)

p.write('6+6\n')

p.read(20)