cs.tty 20201102

Functions related to terminals.

Functions related to terminals.

Latest release 20201102: New modify_termios and stack_termios to apply (and restore) termios modes.

Function modify_termios(fd=0, set_modes=None, clear_modes=None, strict=False)

Apply mode changes to a tty. Return the previous tty modes as from termios.tcgetattr or None if the changes could not be applied. If strict, raise an exception instead of returning None.

Parameters:

• fd: optional tty file descriptor, default 0.
• set_modes: an optional mapping of attribute name to new value for values to set
• clear_modes: an optional mapping of attribute name to new value for values to clear
• strict: optional flag, default False; if true, raise exceptions from failed tcgetattr and tcsetattr calls otherwise issue a warning if the errno is not ENOTTY and proceed. This aims to provide ease of use in batch mode by default while providing a mode to fail overtly if required.

The attribute names are from iflag, oflag, cflag, lflag, ispeed, ospeed, cc, corresponding to the list entries defined by the termios.tcgetattr call.

For set_modes, the attributes ispeed, ospeed and cc are applied directly; the other attributes are binary ORed into the existing modes.

For clear_modes, the attributes ispeed, ospeed and cc cannot be cleared; the other attributes are binary removed from the existing modes.

For example, to turn off the terminal echo during some operation:

old_modes = apply_termios(clear_modes={'lflag': termios.ECHO}):
    ... do something with tty echo disabled ...
if old_modes:
    termios.tcsetattr(fd, termios.TCSANOW, old_modes)

Function setupterm(*args)

Run curses.setupterm, needed to be able to use the status line. Uses a global flag to avoid doing this twice.

Function stack_termios(fd=0, set_modes=None, clear_modes=None, strict=False)

Context manager to apply and restore changes to a tty. Yield the previous tty modes as from termios.tcgetattr or None if the changes could not be applied. If strict, raise an exception instead of yielding None.

Parameters:

• fd: optional tty file descriptor, default 0.
• set_modes: an optional mapping of attribute name to new value for values to set
• clear_modes: an optional mapping of attribute name to new value for values to clear
• strict: optional flag, default False; if true, raise exceptions from failed tcgetattr and tcsetattr calls otherwise issue a warning if the errno is not ENOTTY and proceed. This aims to provide ease of use in batch mode by default while providing a mode to fail overtly if required.

The attribute names are from iflag, oflag, cflag, lflag, ispeed, ospeed, cc, corresponding to the list entries defined by the termios.tcgetattr call.

For set_modes, the attributes ispeed, ospeed and cc are applied directly; the other attributes are binary ORed into the existing modes.

For clear_modes, the attributes ispeed, ospeed and cc cannot be cleared; the other attributes are binary removed from the existing modes.

For example, to turn off the terminal echo during some operation:

with stack_termios(clear_modes={'lflag': termios.ECHO}):
    ... do something with tty echo disabled ...

Function status(msg, *args, **kwargs)

Write a message to the terminal's status line.

Parameters:

• msg: message string
• args: if not empty, the message is %-formatted with args
• file: optional keyword argument specifying the output file. Default: sys.stderr.

Hack: if there is no status line use the xterm title bar sequence :-(

Function statusline(text, fd=None, reverse=False, xpos=None, ypos=None)

Update the status line.

Function statusline_bs(text, reverse=False, xpos=None, ypos=None)

Return a byte string to update the status line.

Function ttysize(fd)

Return a (rows, columns) tuple for the specified file descriptor.

If the window size cannot be determined, None will be returned for either or both of rows and columns.

This function relies on the UNIX stty command.

Class WinSize(builtins.tuple)

WinSize(rows, columns)

Property WinSize.columns

Alias for field number 1

Property WinSize.rows

Alias for field number 0

Release Log

Release 20201102: New modify_termios and stack_termios to apply (and restore) termios modes.

Release 20200521:

• New status() function dragged in from cs.logutils, which uses cs.upd for status() -- needs some refactoring to match with the other functions in cs.tty -- text vs bytes, stdout vs stderr, etc.
• Get warning() from cs.gimmicks.

Release 20190101: Small bugfix for setupterm.

Release 20170903: add statusline and statusline_s functions; ttysize: support BSD stty output format

Release 20160828: Use "install_requires" instead of "requires" in DISTINFO, add PyPI category.

Release 20150116: Initial PyPI release.