How to get the width of terminal window in Ruby

Solution 1:

There is a common unix command:

tput cols

This returns the width of the terminal.

Solution 2:

I've found that on Ubuntu, none of the other methods specified here (ENV['COLUMNS'], tput columns or hirb) give the correct result if the terminal is resized while the Ruby application is running. This is not an issue for scripts, but it is an issue for interactive consoles, such as irb.

The ruby-terminfo gem is the best solution I've find so far to give the correct dimensions after a resize, but it requires that you install an additional gem, and is unix-specific.

The gem's usage is simple:

require 'terminfo'
p TermInfo.screen_size        # [lines, columns]

TermInfo internally uses TIOCGWINSZ ioctl for the screen size.

Alternatively, as mentioned by user83510, highline's system_extensions also works:

require 'highline'
HighLine::SystemExtensions.terminal_size # [columns, lines]

Interally, highline uses stty size on Unix, and other implementations for ncurses and Windows.

To listen for changes to the terminal size (instead of polling), we can trap the SIGWINCH signal:

require 'terminfo'
Signal.trap('SIGWINCH', proc { puts TermInfo.screen_size.inspect })

This is specifically useful for applications using Readline, such as irb:

Signal.trap('SIGWINCH', proc { Readline.set_screen_size(TermInfo.screen_size[0], TermInfo.screen_size[1]) })

Solution 3:

def winsize
 #Ruby 1.9.3 added 'io/console' to the standard library.
 require 'io/console'
 IO.console.winsize
 rescue LoadError
 # This works with older Ruby, but only with systems
 # that have a tput(1) command, such as Unix clones.
[Integer(`tput li`), Integer(`tput co`)]
end

rows, cols = winsize
printf "%d rows by %d columns\n", rows, cols

Link

Solution 4:

If you want your code to work across platforms, here's what I use: http://github.com/cldwalker/hirb/blob/master/lib/hirb/util.rb#L61-71

Also check out the system_extensions file in highline