Ask the operating system. 
#!/usr/bin/env perl

use strict;
use warnings;

chomp(my @lines = `stty -a`);
my ($rows, $columns);
for (@lines) {
    $rows = $1 if /rows (\d+);/;       # linux
    $rows = $1 if /(\d+) rows;/;       # FreeBSD
    $columns = $2 if /columns (\d+);/; # line
    $columns = $1 if /(\d+) columns;/; # FreeBSD
}

print "rows $rows columns $columns\n";

[download]
Outputs; 
rows 45 columns 118

[download]
On my FreeBSD clone.

In reply to Re: bulletproof way of finding size of terminal? by bruceb3
in thread bulletproof way of finding size of terminal? by bcrowell2

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