node_runner.rb

##
# Be lazy and restart your node.js app when you change things.
# Screenshot:  http://img.skitch.com/20100606-mbi52g6knk3n83b6m3eqxr4pa4.png
# INSTALL:  
# $ gem install watchr 
# $ wget http://gist.github.com/raw/427720/2aae1f3b43a256f5ca07a603025d455aa92560e1/node_run
# $ cd YOUR_NODE_APP
# $ watchr node_runner.rb 
#
# NOTES: 
# @influx points out, you can do this with inotify tools also: http://wiki.github.com/rvoicilas/inotify-tools/

class NodeRunner
  attr_accessor :pid

  def initialize
    @pid = nil
  end

  def start
    @pid = fork do
      exec "node app.js"
    end
  end

  def restart
     Process.kill "TERM", @pid
     Process.wait @pid
     start
  end
end

@nr = NodeRunner.new
@nr.start

watch( '.*/*js' ) do |md| 
  puts "#{md[0].inspect} changed... restarting."
  @nr.restart
end