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Help on module telnetlib:

NAME
    telnetlib - TELNET client class.

MODULE REFERENCE
    https://docs.python.org/3.10/library/telnetlib.html

    The following documentation is automatically generated from the Python
    source files.  It may be incomplete, incorrect or include features that
    are considered implementation detail and may vary between Python
    implementations.  When in doubt, consult the module reference at the
    location listed above.

DESCRIPTION
    Based on RFC 854: TELNET Protocol Specification, by J. Postel and
    J. Reynolds

    Example:

    >>> from telnetlib import Telnet
    >>> tn = Telnet('www.python.org', 79)   # connect to finger port
    >>> tn.write(b'guido\r\n')
    >>> print(tn.read_all())
    Login       Name               TTY         Idle    When    Where
    guido    Guido van Rossum      pts/2        <Dec  2 11:10> snag.cnri.reston..

    >>>

    Note that read_all() won't read until eof -- it just reads some data
    -- but it guarantees to read at least one byte unless EOF is hit.

    It is possible to pass a Telnet object to a selector in order to wait until
    more data is available.  Note that in this case, read_eager() may return b''
    even if there was data on the socket, because the protocol negotiation may have
    eaten the data.  This is why EOFError is needed in some cases to distinguish
    between "no data" and "connection closed" (since the socket also appears ready
    for reading when it is closed).

    To do:
    - option negotiation
    - timeout should be intrinsic to the connection object instead of an
      option on one of the read calls only

CLASSES
    builtins.object
        Telnet

    class Telnet(builtins.object)
     |  Telnet(host=None, port=0, timeout=<object object at 0x7f64c1fbca30>)
     |
     |  Telnet interface class.
     |
     |  An instance of this class represents a connection to a telnet
     |  server.  The instance is initially not connected; the open()
     |  method must be used to establish a connection.  Alternatively, the
     |  host name and optional port number can be passed to the
     |  constructor, too.
     |
     |  Don't try to reopen an already connected instance.
     |
     |  This class has many read_*() methods.  Note that some of them
     |  raise EOFError when the end of the connection is read, because
     |  they can return an empty string for other reasons.  See the
     |  individual doc strings.
     |
     |  read_until(expected, [timeout])
     |      Read until the expected string has been seen, or a timeout is
     |      hit (default is no timeout); may block.
     |
     |  read_all()
     |      Read all data until EOF; may block.
     |
     |  read_some()
     |      Read at least one byte or EOF; may block.
     |
     |  read_very_eager()
     |      Read all data available already queued or on the socket,
     |      without blocking.
     |
     |  read_eager()
     |      Read either data already queued or some data available on the
     |      socket, without blocking.
     |
     |  read_lazy()
     |      Read all data in the raw queue (processing it first), without
     |      doing any socket I/O.
     |
     |  read_very_lazy()
     |      Reads all data in the cooked queue, without doing any socket
     |      I/O.
     |
     |  read_sb_data()
     |      Reads available data between SB ... SE sequence. Don't block.
     |
     |  set_option_negotiation_callback(callback)
     |      Each time a telnet option is read on the input flow, this callback
     |      (if set) is called with the following parameters :
     |      callback(telnet socket, command, option)
     |          option will be chr(0) when there is no option.
     |      No other action is done afterwards by telnetlib.
     |
     |  Methods defined here:
     |
     |  __del__(self)
     |      Destructor -- close the connection.
     |
     |  __enter__(self)
     |
     |  __exit__(self, type, value, traceback)
     |
     |  __init__(self, host=None, port=0, timeout=<object object at 0x7f64c1fbca30>)
     |      Constructor.
     |
     |      When called without arguments, create an unconnected instance.
     |      With a hostname argument, it connects the instance; port number
     |      and timeout are optional.
     |
     |  close(self)
     |      Close the connection.
     |
     |  expect(self, list, timeout=None)
     |      Read until one from a list of a regular expressions matches.
     |
     |      The first argument is a list of regular expressions, either
     |      compiled (re.Pattern instances) or uncompiled (strings).
     |      The optional second argument is a timeout, in seconds; default
     |      is no timeout.
     |
     |      Return a tuple of three items: the index in the list of the
     |      first regular expression that matches; the re.Match object
     |      returned; and the text read up till and including the match.
     |
     |      If EOF is read and no text was read, raise EOFError.
     |      Otherwise, when nothing matches, return (-1, None, text) where
     |      text is the text received so far (may be the empty string if a
     |      timeout happened).
     |
     |      If a regular expression ends with a greedy match (e.g. '.*')
     |      or if more than one expression can match the same input, the
     |      results are undeterministic, and may depend on the I/O timing.
     |
     |  fileno(self)
     |      Return the fileno() of the socket object used internally.
     |
     |  fill_rawq(self)
     |      Fill raw queue from exactly one recv() system call.
     |
     |      Block if no data is immediately available.  Set self.eof when
     |      connection is closed.
     |
     |  get_socket(self)
     |      Return the socket object used internally.
     |
     |  interact(self)
     |      Interaction function, emulates a very dumb telnet client.
     |
     |  listener(self)
     |      Helper for mt_interact() -- this executes in the other thread.
     |
     |  msg(self, msg, *args)
     |      Print a debug message, when the debug level is > 0.
     |
     |      If extra arguments are present, they are substituted in the
     |      message using the standard string formatting operator.
     |
     |  mt_interact(self)
     |      Multithreaded version of interact().
     |
     |  open(self, host, port=0, timeout=<object object at 0x7f64c1fbca30>)
     |      Connect to a host.
     |
     |      The optional second argument is the port number, which
     |      defaults to the standard telnet port (23).
     |
     |      Don't try to reopen an already connected instance.
     |
     |  process_rawq(self)
     |      Transfer from raw queue to cooked queue.
     |
     |      Set self.eof when connection is closed.  Don't block unless in
     |      the midst of an IAC sequence.
     |
     |  rawq_getchar(self)
     |      Get next char from raw queue.
     |
     |      Block if no data is immediately available.  Raise EOFError
     |      when connection is closed.
     |
     |  read_all(self)
     |      Read all data until EOF; block until connection closed.
     |
     |  read_eager(self)
     |      Read readily available data.
     |
     |      Raise EOFError if connection closed and no cooked data
     |      available.  Return b'' if no cooked data available otherwise.
     |      Don't block unless in the midst of an IAC sequence.
     |
     |  read_lazy(self)
     |      Process and return data that's already in the queues (lazy).
     |
     |      Raise EOFError if connection closed and no data available.
     |      Return b'' if no cooked data available otherwise.  Don't block
     |      unless in the midst of an IAC sequence.
     |
     |  read_sb_data(self)
     |      Return any data available in the SB ... SE queue.
     |
     |      Return b'' if no SB ... SE available. Should only be called
     |      after seeing a SB or SE command. When a new SB command is
     |      found, old unread SB data will be discarded. Don't block.
     |
     |  read_some(self)
     |      Read at least one byte of cooked data unless EOF is hit.
     |
     |      Return b'' if EOF is hit.  Block if no data is immediately
     |      available.
     |
     |  read_until(self, match, timeout=None)
     |      Read until a given string is encountered or until timeout.
     |
     |      When no match is found, return whatever is available instead,
     |      possibly the empty string.  Raise EOFError if the connection
     |      is closed and no cooked data is available.
     |
     |  read_very_eager(self)
     |      Read everything that's possible without blocking in I/O (eager).
     |
     |      Raise EOFError if connection closed and no cooked data
     |      available.  Return b'' if no cooked data available otherwise.
     |      Don't block unless in the midst of an IAC sequence.
     |
     |  read_very_lazy(self)
     |      Return any data available in the cooked queue (very lazy).
     |
     |      Raise EOFError if connection closed and no data available.
     |      Return b'' if no cooked data available otherwise.  Don't block.
     |
     |  set_debuglevel(self, debuglevel)
     |      Set the debug level.
     |
     |      The higher it is, the more debug output you get (on sys.stdout).
     |
     |  set_option_negotiation_callback(self, callback)
     |      Provide a callback function called after each receipt of a telnet option.
     |
     |  sock_avail(self)
     |      Test whether data is available on the socket.
     |
     |  write(self, buffer)
     |      Write a string to the socket, doubling any IAC characters.
     |
     |      Can block if the connection is blocked.  May raise
     |      OSError if the connection is closed.
     |
     |  ----------------------------------------------------------------------
     |  Data descriptors defined here:
     |
     |  __dict__
     |      dictionary for instance variables (if defined)
     |
     |  __weakref__
     |      list of weak references to the object (if defined)

DATA
    __all__ = ['Telnet']

FILE
    /usr/lib/python3.10/telnetlib.py