How to get console window width in python

Question

Is there a way in python to programmatically determine the width of the console? I mean the number of characters that fits in one line without wrapping, not the pixel width of the window.

Edit

Looking for a solution that works on Linux

Answer 1

use

import console
(width, height) = console.getTerminalSize()

print "Your terminal's width is: %d" % width

EDIT: oh, I'm sorry. That's not a python standard lib one, here's the source of console.py (I don't know where it's from).

The module seems to work like that: It checks if termcap is available, when yes. It uses that; if no it checks whether the terminal supports a special ioctl call and that does not work, too, it checks for the environment variables some shells export for that. This will probably work on UNIX only.

def getTerminalSize():
    def ioctl_GWINSZ(fd):
        try:
            import fcntl, termios, struct, os
            cr = struct.unpack('hh', fcntl.ioctl(fd, termios.TIOCGWINSZ,
        '1234'))
        except:
            return None
        return cr
    cr = ioctl_GWINSZ(0) or ioctl_GWINSZ(1) or ioctl_GWINSZ(2)
    if not cr:
        try:
            fd = os.open(os.ctermid(), os.O_RDONLY)
            cr = ioctl_GWINSZ(fd)
            os.close(fd)
        except:
            pass
    if not cr:
        try:
            cr = (env['LINES'], env['COLUMNS'])
        except:
            cr = (25, 80)
    return int(cr[1]), int(cr[0])

Answer 2

Depending on your shell (I know that bash, at least, does this), you can access the terminal size using the ROWS and COLUMNS environment variables. I don't know of a Windows equivalent.

import os
print os.environ["COLUMNS"]

Answer 3

import os
rows, columns = os.popen('stty size', 'r').read().split()

uses the 'stty size' command which according to a thread on the python mailing list is reasonably universal on linux. It opens the 'stty size' command as a file, 'reads' from it, and uses a simple string split to separate the coordinates.

Unlike the os.environ["COLUMNS"] value (which I can't access in spite of using bash as my standard shell) the data will also be up-to-date whereas I believe the os.environ["COLUMNS"] value would only be valid for the time of the launch of the python interpreter (suppose the user resized the window since then).

Answer 4

Code above didn't return correct result on my linux because winsize-struct has 4 unsigned shorts, not 2 signed shorts:

def terminal_size():
    import fcntl, termios, struct
    h, w, hp, wp = struct.unpack('HHHH',
        fcntl.ioctl(0, termios.TIOCGWINSZ,
        struct.pack('HHHH', 0, 0, 0, 0)))
    return w, h

hp and hp should contain pixel width and height, but don't.

Answer 5

It looks like there are some problems with that code, Johannes:

• getTerminalSize needs to import os
• what is env? looks like os.environ.

Also, why switch lines and cols before returning? If TIOCGWINSZ and stty both say lines then cols, I say leave it that way. This confused me for a good 10 minutes before I noticed the inconsistency.

Sridhar, I didn't get that error when I piped output. I'm pretty sure it's being caught properly in the try-except.

pascal, "HHHH" doesn't work on my machine, but "hh" does. I had trouble finding documentation for that function. It looks like it's platform dependent.

chochem, incorporated.

Here's my version:

def getTerminalSize():
    """
    returns (lines:int, cols:int)
    """
    import os, struct
    def ioctl_GWINSZ(fd):
        import fcntl, termios
        return struct.unpack("hh", fcntl.ioctl(fd, termios.TIOCGWINSZ, "1234"))
    # try stdin, stdout, stderr
    for fd in (0, 1, 2):
        try:
            return ioctl_GWINSZ(fd)
        except:
            pass
    # try os.ctermid()
    try:
        fd = os.open(os.ctermid(), os.O_RDONLY)
        try:
            return ioctl_GWINSZ(fd)
        finally:
            os.close(fd)
    except:
        pass
    # try `stty size`
    try:
        return tuple(int(x) for x in os.popen("stty size", "r").read().split())
    except:
        pass
    # try environment variables
    try:
        return tuple(int(os.getenv(var)) for var in ("LINES", "COLUMNS"))
    except:
        pass
    # i give up. return default.
    return (25, 80)