Script to turn on or off `Do Not Disturb` mode on Mac OS X from console

do_not_disturb.rb

#!/usr/bin/env ruby

# Get current status of Do Not Disturb mode by reading specific plist file
#
# @return [TrueClass,FalseClass] true if the mode is active
#
def do_not_disturb
  plist_file = Dir.glob(Dir.home + '/Library/Preferences/ByHost/com.apple.notificationcenterui.*.plist').last
  `/usr/libexec/PlistBuddy -c "Print doNotDisturb" "#{plist_file}"`.strip == 'true'
end

# Set status of Do Not Disturb mode
# 
# @warning this method can take about 4 seconds to run, it is wating until the value is written to plist files
#
# @param [TrueClass,FalseClass] enabled true if the mode should be active
#
def do_not_disturb=(enabled)
  if enabled != do_not_disturb
    toggle_do_not_disturb_mode

    while enabled != do_not_disturb
      sleep 0.1
    end
  end
end

# Toggle status of Do Not Disturb mode
#
def toggle_do_not_disturb_mode
  script = <<-EOD
      tell application "System Events" to tell process "SystemUIServer"
        key down option
        
        try
          click menu bar item 1 of menu bar 2
        on error errMsg
          log "something is wrong, maybe the Terminal.app don't have permissons to perform clicks, try enabling in System Preferences > Security & Privace > Privacy > Accessibility"
        end try
        
        key up option
      end tell
  EOD

  system('osascript', '-e', script)
end

# Prints help to stream
#
def print_help(stream)
  stream.puts "Tool to turn on or off `Do Not Disturb` mode on Mac OS X"
  stream.puts "Usage: #{File.basename($PROGRAM_NAME)} (on|off)"
end

def validate_input_value
  if ARGV.count != 1
    print_help($stderr)
    exit 1
  end

  value = ARGV[0]

  if value == '--help'
    print_help($stdout)
    exit 0
  end

  valid_values = %w(on off)
  unless valid_values.include?(value)
    $stderr.puts "Invalid input `#{value}`, valid ones are #{valid_values}."
    exit 1
  end

  value
end

self.do_not_disturb = validate_input_value == 'on'