Try to find the size of a terminal window.

termsize.py

import fcntl
import os
import struct
import sys
import termios

def window_size(fd):
    """Try to get the size of a terminal window.

    :param fd: The file descriptor of the terminal window.
    :return: The size of the terminal window as a tuple (width, height), or None
             if it cannot be determined.

    """
    try:
        # Make an IOCTL call to get the size. The second argument is a constant
        # telling IOCTL we want the size. The third argument is a string
        # of the same length as the output data, in this case four bytes (two
        # each for width and height).
        s = fcntl.ioctl(fd, termios.TIOCGWINSZ, '1234')

        # Unpack the resulting structure into two values.
        size = struct.unpack('hh', s)
    except:
        return None

    # Flip the result into the desired order and ensure the values are integers.
    return (int(size[1]), int(size[0]))

def terminal_size():
    """Try to get the size of the current terminal. The following series of
    steps is used to get the size:

    * Try to get the size from one of the sys.stdout, sys.stderr or sys.stdin
      file descriptors.
    * If that fails, open the controlling terminal of the process (defined in
      os.ctermid) and try to get the size from that.
    * If that fails, try reading it from the LINES and COLUMNS environment
      variables.
    * Finally, default to an 80x24 terminal.

    :return: The size of the current terminal window as a tuple (width, height).

    """
    # Try getting it from one of the standard file descriptors.
    print 'Trying IOCTL on stdout...'
    size = window_size(sys.stdout.fileno())
    if not size:
        print 'Trying IOCTL on stderr...'
        size = window_size(sys.stderr.fileno())
    if not size:
        print 'Trying IOCTL on stdin...'
        size = window_size(sys.stdin.fileno())

    # If that didn't work, open the controlling terminal and try getting the
    # size from there.
    if not size:
        print 'Trying IOCTL on controlling terminal...'
        try:
            fd = os.open(os.ctermid(), os.O_RDONLY)
            size = window_size(fd)
            os.close(fd)
        except:
            pass

    # If that didn't work, try the environment variables.
    if not size:
        print 'Trying COLUMNS/LINES shell variables...'
        try:
            size = (os.environ['COLUMNS'], os.environ['LINES'])
        except:
            pass

    # Unable to find the real size, assume 80x24.
    if not size:
        print 'Assuming 80x24...'
        size = (80, 24)

    # Done.
    return size

print terminal_size()