Automatically configure screens

gistfile1.rb

#!/usr/bin/env ruby

EXTERNAL_SCREEN = 'VGA1'
LAPTOP_SCREEN = 'LVDS1'

def use_external_screen
  system "xrandr --output #{EXTERNAL_SCREEN} --auto && xrandr --output #{LAPTOP_SCREEN} --off"
end

def use_laptop_screen
  system "xrandr --output #{LAPTOP_SCREEN} --auto && xrandr --output #{EXTERNAL_SCREEN} --off"
end

def is_vga_connected?
  IO.popen('xrandr -q | grep " connected "').each do |l|
    return true if l =~ /#{EXTERNAL_SCREEN}/
  end
  return false
end

loop {
  if is_vga_connected?
    use_external_screen
  else
    use_laptop_screen
  end
sleep 5
}

There is no need for the daemons gem.
You should execute this file within your .xinitrc and background it by appending &.

Yeah, you are absolutely right. I don't use .xinitrc though, but I suppose it should work as well