Term::Size(3) Retrieve terminal size (Unix version)


use Term::Size;
($columns, $rows) = Term::Size::chars *STDOUT{IO};
($x, $y) = Term::Size::pixels;


Term::Size is a Perl module which provides a straightforward way to retrieve the terminal size.

Both functions take an optional filehandle argument, which defaults to *STDIN{IO}. They both return a list of two values, which are the current width and height, respectively, of the terminal associated with the specified filehandle.

"Term::Size::chars" returns the size in units of characters, whereas "Term::Size::pixels" uses units of pixels.

In a scalar context, both functions return the first element of the list, that is, the terminal width.

The functions may be imported.

If you need to pass a filehandle to either of the "Term::Size" functions, beware that the *STDOUT{IO} syntax is only supported in Perl 5.004 and later. If you have an earlier version of Perl, or are interested in backwards compatibility, use *STDOUT instead.


1. Refuse to run in a too narrow window.

    use Term::Size;
    die "Need 80 column screen" if Term::Size::chars *STDOUT{IO} < 80;

2. Track window size changes.

    use Term::Size 'chars';
    my $changed = 1;
    while (1) {
            local $SIG{'WINCH'} = sub { $changed = 1 };
            if ($changed) {
                    ($cols, $rows) = chars;
                    # Redraw, or whatever.
                    $changed = 0;


Both functions return "undef" if there is an error.

If the terminal size information is not available, the functions will normally return "(0, 0)", but this depends on your system. On character only terminals, "pixels" will normally return "(0, 0)".


It only works on Unix systems.


Tim Goodwin, <[email protected]>, 1997-04-23.

Candidate for maintainership: Adriano Ferreira, <[email protected]>, 2006-05-19.