ruby-winsize

ruby-winsize is a small library that lets you get and set the winsize of a terminal.

ruby-winsize adds two methods (winsize and winsize=) to for use with any IO instance for a TTY device. The Winsize::Winsize class is an intermediate form that is used for ioctl calls to the TTY device.

Installing

Recommended

gem install winsize

Edge

git clone https://github.com/samuelkadolph/ruby-winsize
cd ruby-winsize && rake install

Usage

To get the size of the $stdout terminal.

require "winsize"

size = $stdout.winsize
puts "Your terminal is #{size.columns}x#{size.rows}"
puts "Your terminal is #{size.horizontal_pixels}px*#{size.vertical_pixels}px"

To set the size of a pty terminal. This is useful if you are running a subshell and want the subshell to have the same output size as the terminal you yourself are running in.

You might think it would be useful to set the winsize of $stdout it actually isn't since the terminal is usually limited by the monitor size or the terminal application and increasing the size messes with trimming logic.

require "pty"
require "winsize"

size = Winsize.new(32, 160)
# or
# size = $stdout.winsize

in, out, pid = PTY.spawn

out.winsize = winsize
# or
# out.winsize = 32, 160

You may want to combine winsize and catching the SIGWINCH signal so you update something that your terminal has been resized.

require "winsize"

puts "Terminal size is #{$stdout.winsize.columns}x#{$stdout.winsize.rows}"

Signal.trap "WINCH" do
  puts "Terminal resized to #{$stdout.winsize.columns}x#{$stdout.winsize.rows}"
end