(un)Block distracting sites in hosts file via quick and dirty script. Inspired by http://al3x.net/2009/09/14/my-get-back-to-work-hack.html

focus.rb

#!/usr/bin/env ruby

## you will probably need to run this via sudo
## sudo ruby focus.rb [on|off]

# inspired by http://al3x.net/2009/09/14/my-get-back-to-work-hack.html

require 'fileutils'
require 'tempfile'

class Focus
  HOSTS_FILE = "/etc/hosts"
  HOSTS_FILE_BACKUP = "/etc/hosts.bak"
  DISTRACTIONS_START = "#begin_distractions"
  DISTRACTIONS_END = "#end_distractions"
  DISTRACTION_HOSTS = [
                       "news.ycombinator.com",
                       "twitter.com www.twitter.com",
                       "techmeme.com www.techmeme.com",
                       "techcrunch.com www.techcrunch.com",
                       "reddit.com www.reddit.com",
                       "hacker-newspaper.gilesb.com",
                       "icombinator.net www.icombinator.net",
                       "readwriteweb.com www.readwriteweb.com",
                       "gizmodo.com www.gizmodo.com",
                       "engadget.com www.engadget.com",
                       "tuaw.com www.tuaw.com",
                       "macnn.com www.macnn.com",
                       "arstechnica.com www.arstechnica.com",
                       "digg.com www.digg.com",
                       "wired.com www.wired.com",
                       "cnet.com www.cnet.com",
                       "zdnet.com www.zdnet.com",
                       "mashable.com www.mashable.com",
                       "boingboing.net www.boingboing.net",
                       "lifehacker.com www.lifehacker.com",
                       "gawker.com www.gawker.com",
                       "nytimes.com www.nytimes.com",
                       "tweetmeme.com www.tweetmeme.com",
                       "venturebeat.com www.venturebeat.com",
                       "torrentfreak.com www.torrentfreak.com",
                       "kottke.org www.kottke.org",
                       "daringfireball.net www.daringfireball.net",
                       "metafilter.com www.metafilter.com",
                       "codinghorror.com www.codinghorror.com",
                       "zenhabits.net www.zenhabits.net",
                       "macrumors.com www.macrumors.com",
                       "radar.oreilly.com",
                       "engadgetmobile.com www.engadgetmobile.com",
                       "gigaom.com www.gigaom.com",
                       "crunchgear.com www.crunchgear.com",
                       "news.google.com"
                      ]

  def off
    update_hosts
  end

  def on
    update_hosts(DISTRACTION_HOSTS)
  end

  private

  def update_hosts(distractions = [])
    # backup hosts
    FileUtils.cp HOSTS_FILE, HOSTS_FILE_BACKUP

    in_distractions = false
    Tempfile.open("hosts") do |temp|
      File.foreach(HOSTS_FILE) do |line|
        if line =~ /^#{DISTRACTIONS_START}/
          in_distractions = true
        end

        temp.puts line unless in_distractions

        if line =~ /^#{DISTRACTIONS_END}/
          in_distractions = false
        end
      end

      unless distractions.empty?
        temp.puts DISTRACTIONS_START
        distractions.each do |host|
          temp.puts "127.0.0.1 #{host}"
        end
        temp.puts DISTRACTIONS_END
      end

      temp.close
      FileUtils.cp temp.path, HOSTS_FILE
    end
  end
end

focus = Focus.new
case ARGV[0]
when /stop|off/
  focus.off
else
  focus.on
end