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+:mod:`termios` --- POSIX style tty control
+==========================================
+
+.. module:: termios
+   :platform: Unix
+   :synopsis: POSIX style tty control.
+
+.. index::
+   pair: POSIX; I/O control
+   pair: tty; I/O control
+
+--------------
+
+This module provides an interface to the POSIX calls for tty I/O control. For a
+complete description of these calls, see :manpage:`termios(3)` Unix manual
+page.  It is only available for those Unix versions that support POSIX
+*termios* style tty I/O control configured during installation.
+
+All functions in this module take a file descriptor *fd* as their first
+argument.  This can be an integer file descriptor, such as returned by
+``sys.stdin.fileno()``, or a :term:`file object`, such as ``sys.stdin`` itself.
+
+This module also defines all the constants needed to work with the functions
+provided here; these have the same name as their counterparts in C.  Please
+refer to your system documentation for more information on using these terminal
+control interfaces.
+
+The module defines the following functions:
+
+
+.. function:: tcgetattr(fd)
+
+   Return a list containing the tty attributes for file descriptor *fd*, as
+   follows: ``[iflag, oflag, cflag, lflag, ispeed, ospeed, cc]`` where *cc* is a
+   list of the tty special characters (each a string of length 1, except the
+   items with indices :const:`VMIN` and :const:`VTIME`, which are integers when
+   these fields are defined).  The interpretation of the flags and the speeds as
+   well as the indexing in the *cc* array must be done using the symbolic
+   constants defined in the :mod:`termios` module.
+
+
+.. function:: tcsetattr(fd, when, attributes)
+
+   Set the tty attributes for file descriptor *fd* from the *attributes*, which is
+   a list like the one returned by :func:`tcgetattr`.  The *when* argument
+   determines when the attributes are changed: :const:`TCSANOW` to change
+   immediately, :const:`TCSADRAIN` to change after transmitting all queued output,
+   or :const:`TCSAFLUSH` to change after transmitting all queued output and
+   discarding all queued input.
+
+
+.. function:: tcsendbreak(fd, duration)
+
+   Send a break on file descriptor *fd*.  A zero *duration* sends a break for
+   0.25--0.5 seconds; a nonzero *duration* has a system dependent meaning.
+
+
+.. function:: tcdrain(fd)
+
+   Wait until all output written to file descriptor *fd* has been transmitted.
+
+
+.. function:: tcflush(fd, queue)
+
+   Discard queued data on file descriptor *fd*.  The *queue* selector specifies
+   which queue: :const:`TCIFLUSH` for the input queue, :const:`TCOFLUSH` for the
+   output queue, or :const:`TCIOFLUSH` for both queues.
+
+
+.. function:: tcflow(fd, action)
+
+   Suspend or resume input or output on file descriptor *fd*.  The *action*
+   argument can be :const:`TCOOFF` to suspend output, :const:`TCOON` to restart
+   output, :const:`TCIOFF` to suspend input, or :const:`TCION` to restart input.
+
+
+.. seealso::
+
+   Module :mod:`tty`
+      Convenience functions for common terminal control operations.
+
+
+.. _termios-example:
+
+Example
+-------
+
+Here's a function that prompts for a password with echoing turned off.  Note the
+technique using a separate :func:`tcgetattr` call and a :keyword:`try` ...
+:keyword:`finally` statement to ensure that the old tty attributes are restored
+exactly no matter what happens::
+
+   def getpass(prompt="Password: "):
+       import termios, sys
+       fd = sys.stdin.fileno()
+       old = termios.tcgetattr(fd)
+       new = termios.tcgetattr(fd)
+       new[3] = new[3] & ~termios.ECHO          # lflags
+       try:
+           termios.tcsetattr(fd, termios.TCSADRAIN, new)
+           passwd = input(prompt)
+       finally:
+           termios.tcsetattr(fd, termios.TCSADRAIN, old)
+       return passwd
+