diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..cc32da4
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1 @@
+inherit_from: .rubocop_todo.yml
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
new file mode 100644
index 0000000..f4c4c89
--- /dev/null
+++ b/.rubocop_todo.yml
@@ -0,0 +1,101 @@
+# This configuration was generated by
+# `rubocop --auto-gen-config`
+# on 2016-05-18 02:46:59 +0200 using RuboCop version 0.40.0.
+# The point is for the user to remove these configuration records
+# one by one as the offenses are removed from the code base.
+# Note that changes in the inspected code, or installation of new
+# versions of RuboCop, may require this file to be generated again.
+
+# Offense count: 6
+# Configuration parameters: CountComments.
+Metrics/ClassLength:
+  Max: 485
+
+# Offense count: 3
+# Configuration parameters: CountComments.
+Metrics/MethodLength:
+  Max: 18
+
+# Offense count: 5
+# Configuration parameters: CountComments.
+Metrics/ModuleLength:
+  Max: 334
+
+# Offense count: 10
+Style/Documentation:
+  Exclude:
+    - 'spec/**/*'
+    - 'test/**/*'
+    - 'lib/notiffany.rb'
+    - 'lib/notiffany/notifier.rb'
+    - 'lib/notiffany/notifier/base.rb'
+    - 'lib/notiffany/notifier/detected.rb'
+    - 'lib/notiffany/notifier/tmux.rb'
+
+# Offense count: 52
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: leading, trailing
+Style/DotPosition:
+  Enabled: false
+
+# Offense count: 11
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: symmetrical, new_line, same_line
+Style/MultilineMethodCallBraceLayout:
+  Exclude:
+    - 'spec/lib/notiffany/notifier/growl_spec.rb'
+    - 'spec/lib/notiffany/notifier/libnotify_spec.rb'
+    - 'spec/lib/notiffany/notifier/rb_notifu_spec.rb'
+    - 'spec/lib/notiffany/notifier/terminal_notifier_spec.rb'
+    - 'spec/lib/notiffany/notifier/tmux_spec.rb'
+
+# Offense count: 25
+# Cop supports --auto-correct.
+Style/MutableConstant:
+  Exclude:
+    - 'lib/notiffany/notifier.rb'
+    - 'lib/notiffany/notifier/base.rb'
+    - 'lib/notiffany/notifier/detected.rb'
+    - 'lib/notiffany/notifier/file.rb'
+    - 'lib/notiffany/notifier/gntp.rb'
+    - 'lib/notiffany/notifier/growl.rb'
+    - 'lib/notiffany/notifier/libnotify.rb'
+    - 'lib/notiffany/notifier/notifysend.rb'
+    - 'lib/notiffany/notifier/rb_notifu.rb'
+    - 'lib/notiffany/notifier/terminal_notifier.rb'
+    - 'lib/notiffany/notifier/terminal_title.rb'
+    - 'lib/notiffany/notifier/tmux.rb'
+    - 'lib/notiffany/version.rb'
+    - 'spec/lib/notiffany/notifier/base_spec.rb'
+
+# Offense count: 23
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: only_raise, only_fail, semantic
+Style/SignalException:
+  Exclude:
+    - 'lib/notiffany/notifier.rb'
+    - 'lib/notiffany/notifier/base.rb'
+    - 'lib/notiffany/notifier/detected.rb'
+    - 'lib/notiffany/notifier/file.rb'
+    - 'lib/notiffany/notifier/growl.rb'
+    - 'lib/notiffany/notifier/notifysend.rb'
+    - 'lib/notiffany/notifier/terminal_notifier.rb'
+    - 'lib/notiffany/notifier/tmux.rb'
+    - 'spec/lib/notiffany/notifier/detected_spec.rb'
+
+# Offense count: 13
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: use_perl_names, use_english_names
+Style/SpecialGlobalVars:
+  Enabled: false
+
+# Offense count: 967
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles, ConsistentQuotesInMultiline.
+# SupportedStyles: single_quotes, double_quotes
+Style/StringLiterals:
+  Enabled: false
diff --git a/.travis.yml b/.travis.yml
index 49a3603..649829e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,14 +1,9 @@
 language: ruby
 bundler_args: --without development
 rvm:
-  - 1.9.3
-  - 2.0.0
-  - 2.1.5
   - ruby-head
-  - jruby
-  - rbx-2
-matrix:
-  allow_failures:
-    - rvm: rbx-2
-    - rvm: jruby
+  - 2.2.5
+  - 2.3.1
+  - jruby-9.0.5.0
 sudo: false
+cache: bundler
diff --git a/Gemfile b/Gemfile
index ba59da4..976d23a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,13 +3,16 @@ source 'https://rubygems.org'
 # Specify your gem's dependencies in notiffany.gemspec
 gemspec development_group: :gem_build_tools
 
-gem "rake", "~> 10.0"
-gem 'nenv', "~> 0.1"
+gem "rake", "~> 11.1"
+gem 'nenv', "~> 0.3"
 
 group :test do
-  gem "rspec", "~> 3.1"
+  gem "rspec", "~> 3.4"
 end
 
 group :development do
-  gem 'guard-rspec', "~> 4.5", require: false
+  gem 'guard-rspec', "~> 4.6", require: false
+  gem 'listen', "~> 3.1"
+  gem 'guard-rubocop', "~> 1.2", require: false
+  gem 'rubocop', '~> 0.40', require: false
 end
diff --git a/Guardfile b/Guardfile
index 2ed9a34..b2eda88 100644
--- a/Guardfile
+++ b/Guardfile
@@ -24,7 +24,7 @@
 #
 # and, you'll have to watch "config/Guardfile" instead of "Guardfile"
 #
-watch ("Guardfile") do
+watch("Guardfile") do
   UI.info "Exiting because Guard must be restarted for changes to take effect"
   exit 0
 end
@@ -38,19 +38,26 @@ end
 #  * zeus: 'zeus rspec' (requires the server to be started separately)
 #  * 'just' rspec: 'rspec'
 
-guard :rspec, cmd: "bundle exec rspec" do
-  require "guard/rspec/dsl"
-  dsl = Guard::RSpec::Dsl.new(self)
+group :specs, halt_on_fail: true do
+  guard :rspec, cmd: "bundle exec rspec" do
+    require "guard/rspec/dsl"
+    dsl = Guard::RSpec::Dsl.new(self)
 
-  # Feel free to open issues for suggestions and improvements
+    # Feel free to open issues for suggestions and improvements
 
-  # RSpec files
-  rspec = dsl.rspec
-  watch(rspec.spec_helper) { rspec.spec_dir }
-  watch(rspec.spec_support) { rspec.spec_dir }
-  watch(rspec.spec_files)
+    # RSpec files
+    rspec = dsl.rspec
+    watch(rspec.spec_helper) { rspec.spec_dir }
+    watch(rspec.spec_support) { rspec.spec_dir }
+    watch(rspec.spec_files)
 
-  # Ruby files
-  ruby = dsl.ruby
-  dsl.watch_spec_files_for(ruby.lib_files)
+    # Ruby files
+    ruby = dsl.ruby
+    dsl.watch_spec_files_for(ruby.lib_files)
+  end
+
+  guard :rubocop do
+    watch(/.+\.rb$/)
+    watch(%r{(?:.+/)?\.rubocop(?:_todo)\.yml$}) { |m| File.dirname(m[0]) }
+  end
 end
diff --git a/Rakefile b/Rakefile
index a259cc7..74ae0ef 100644
--- a/Rakefile
+++ b/Rakefile
@@ -5,9 +5,8 @@ require 'nenv'
 default_tasks = []
 
 require 'rspec/core/rake_task'
-default_tasks  << RSpec::Core::RakeTask.new(:spec) do |t|
+default_tasks << RSpec::Core::RakeTask.new(:spec) do |t|
   t.verbose = Nenv.ci?
 end
 
 task default: default_tasks.map(&:name)
-
diff --git a/lib/notiffany/notifier.rb b/lib/notiffany/notifier.rb
index 173b7fd..47fcf20 100644
--- a/lib/notiffany/notifier.rb
+++ b/lib/notiffany/notifier.rb
@@ -2,9 +2,9 @@
 require "rbconfig"
 require "pathname"
 require "nenv"
-require "logger"
 
 require "notiffany/notifier/detected"
+require "notiffany/notifier/config"
 
 module Notiffany
   # The notifier handles sending messages to different notifiers. Currently the
@@ -43,9 +43,7 @@ def self.connect(options = {})
   end
 
   class Notifier
-    DEFAULTS = { notify: true }
-
-    NOTIFICATIONS_DISABLED = "Notifications disabled by GUARD_NOTIFY" +
+    NOTIFICATIONS_DISABLED = "Notifications disabled by GUARD_NOTIFY" \
       " environment variable"
 
     USING_NOTIFIER = "Notiffany is using %s to send notifications."
@@ -79,35 +77,16 @@ class Notifier
     class NotServer < RuntimeError
     end
 
-    def initialize(opts)
-      @env_namespace = opts.fetch(:namespace, "notiffany")
-      @logger = opts.fetch(:logger) do
-        Logger.new($stderr).tap { |l| l.level = Logger::WARN }
-      end
+    attr_reader :config
 
-
-      @detected = Detected.new(SUPPORTED, @env_namespace, @logger)
+    def initialize(opts)
+      @config = Config.new(opts)
+      @detected = Detected.new(SUPPORTED, config.env_namespace, config.logger)
       return if _client?
 
-      _env.notify_pid = $$
-
-      fail "Already connected" if active?
-
-      options = DEFAULTS.merge(opts)
-      return unless enabled? && options[:notify]
-
-      notifiers = opts.fetch(:notifiers, {})
-      if notifiers.any?
-        notifiers.each do |name, notifier_options|
-          @detected.add(name, notifier_options)
-        end
-      else
-        @detected.detect
-      end
-
-      turn_on
+      _activate
     rescue Detected::NoneAvailableError => e
-      @logger.info e.to_s
+      config.logger.info e.to_s
     end
 
     def disconnect
@@ -133,13 +112,7 @@ def turn_on(options = {})
 
       fail "Already active!" if active?
 
-      silent = options[:silent]
-
-      @detected.available.each do |obj|
-        @logger.debug(format(USING_NOTIFIER, obj.title)) unless silent
-        obj.turn_on if obj.respond_to?(:turn_on)
-      end
-
+      _turn_on_notifiers(options)
       _env.notify_active = true
     end
 
@@ -191,7 +164,7 @@ def available
     private
 
     def _env
-      @environment ||= Env.new(@env_namespace)
+      @environment ||= Env.new(config.env_namespace)
     end
 
     def _check_server!
@@ -201,5 +174,37 @@ def _check_server!
     def _client?
       (pid = _env.notify_pid) && (pid != $$)
     end
+
+    def _detect_or_add_notifiers
+      notifiers = config.notifiers
+      return @detected.detect if notifiers.empty?
+
+      notifiers.each do |name, notifier_options|
+        @detected.add(name, notifier_options)
+      end
+    end
+
+    def _notification_wanted?
+      enabled? && config.notify?
+    end
+
+    def _activate
+      _env.notify_pid = $$
+
+      fail "Already connected" if active?
+
+      return unless _notification_wanted?
+
+      _detect_or_add_notifiers
+      turn_on
+    end
+
+    def _turn_on_notifiers(options)
+      silent = options[:silent]
+      @detected.available.each do |obj|
+        config.logger.debug(format(USING_NOTIFIER, obj.title)) unless silent
+        obj.turn_on if obj.respond_to?(:turn_on)
+      end
+    end
   end
 end
diff --git a/lib/notiffany/notifier/base.rb b/lib/notiffany/notifier/base.rb
index 5068ecd..4313126 100644
--- a/lib/notiffany/notifier/base.rb
+++ b/lib/notiffany/notifier/base.rb
@@ -38,7 +38,7 @@ def initialize(gem_name)
 
       class UnsupportedPlatform < UnavailableError
         def initialize
-          super "Unsupported platform #{RbConfig::CONFIG["host_os"].inspect}"
+          super "Unsupported platform #{RbConfig::CONFIG['host_os'].inspect}"
         end
       end
 
diff --git a/lib/notiffany/notifier/config.rb b/lib/notiffany/notifier/config.rb
new file mode 100644
index 0000000..4a7757a
--- /dev/null
+++ b/lib/notiffany/notifier/config.rb
@@ -0,0 +1,34 @@
+require "logger"
+
+module Notiffany
+  class Notifier
+    # Configuration class for Notifier
+    class Config
+      DEFAULTS = { notify: true }.freeze
+
+      attr_reader :env_namespace
+      attr_reader :logger
+      attr_reader :notifiers
+
+      def initialize(opts)
+        options = DEFAULTS.merge(opts)
+        @env_namespace = opts.fetch(:namespace, "notiffany")
+        @logger = _setup_logger(options)
+        @notify = options[:notify]
+        @notifiers = opts.fetch(:notifiers, {})
+      end
+
+      def notify?
+        @notify
+      end
+
+      private
+
+      def _setup_logger(opts)
+        opts.fetch(:logger) do
+          Logger.new($stderr).tap { |l| l.level = Logger::WARN }
+        end
+      end
+    end
+  end
+end
diff --git a/lib/notiffany/notifier/detected.rb b/lib/notiffany/notifier/detected.rb
index fa909f5..63dec16 100644
--- a/lib/notiffany/notifier/detected.rb
+++ b/lib/notiffany/notifier/detected.rb
@@ -19,8 +19,8 @@ class Notifier
     # TODO: use a socket instead of passing env variables to child processes
     # (currently probably only used by guard-cucumber anyway)
     YamlEnvStorage = Nenv::Builder.build do
-      create_method(:notifiers=) { |data| YAML::dump(data || []) }
-      create_method(:notifiers) { |data| data ? YAML::load(data) : [] }
+      create_method(:notifiers=) { |data| YAML.dump(data || []) }
+      create_method(:notifiers) { |data| data ? YAML.load(data) : [] }
     end
 
     # @private api
@@ -37,9 +37,7 @@ def initialize(name)
           @name = name
         end
 
-        def name
-          @name
-        end
+        attr_reader :name
 
         def message
           "Unknown notifier: #{@name.inspect}"
@@ -61,7 +59,7 @@ def detect
         @supported.each do |group|
           group.detect do |name, _|
             begin
-              add(name, {})
+              _add(name, {})
               true
             rescue Notifier::Base::UnavailableError => e
               @logger.debug "Notiffany: #{name} not available (#{e.message})."
@@ -79,7 +77,17 @@ def available
         end
       end
 
+      # Called when user has notifier-specific config.
+      # Honor the config by warning if something is wrong
       def add(name, opts)
+        _add(name, opts)
+      rescue Notifier::Base::UnavailableError => e
+        @logger.warning("Notiffany: #{name} not available (#{e.message}).")
+      end
+
+      private
+
+      def _add(name, opts)
         @available = nil
         all = _notifiers
 
@@ -98,8 +106,6 @@ def add(name, opts)
         all.each { |item| item[:options] = opts if item[:name] == name }
       end
 
-      private
-
       def _to_module(name)
         @supported.each do |group|
           next unless (notifier = group.detect { |n, _| n == name })
diff --git a/lib/notiffany/notifier/file.rb b/lib/notiffany/notifier/file.rb
index fa4ab9c..e83bff7 100644
--- a/lib/notiffany/notifier/file.rb
+++ b/lib/notiffany/notifier/file.rb
@@ -32,8 +32,8 @@ def _check_available(opts = {})
       def _perform_notify(message, opts = {})
         fail UnavailableError, "No :path option given" unless opts[:path]
 
-        format = opts[:format]
-        ::File.write(opts[:path], format % [opts[:type], opts[:title], message])
+        str = format(opts[:format], opts[:type], opts[:title], message)
+        ::File.write(opts[:path], str)
       end
 
       def _gem_name
diff --git a/lib/notiffany/notifier/gntp.rb b/lib/notiffany/notifier/gntp.rb
index cc3cf0b..6695cf7 100644
--- a/lib/notiffany/notifier/gntp.rb
+++ b/lib/notiffany/notifier/gntp.rb
@@ -24,11 +24,12 @@ class GNTP < Base
       CLIENT_DEFAULTS = {
         host:     "127.0.0.1",
         password: "",
-        port:     23053
+        port:     23_053
       }
 
       def _supported_hosts
-        %w(darwin linux linux-gnu freebsd openbsd sunos solaris mswin mingw cygwin)
+        %w(darwin linux linux-gnu freebsd openbsd sunos solaris mswin mingw
+           cygwin)
       end
 
       def _gem_name
diff --git a/lib/notiffany/notifier/notifysend.rb b/lib/notiffany/notifier/notifysend.rb
index f375dc4..5c27015 100644
--- a/lib/notiffany/notifier/notifysend.rb
+++ b/lib/notiffany/notifier/notifysend.rb
@@ -26,7 +26,7 @@ class NotifySend < Base
       def _gem_name
         nil
       end
-      
+
       def _supported_hosts
         %w(linux linux-gnu freebsd openbsd sunos solaris)
       end
@@ -81,7 +81,7 @@ def _notifysend_urgency(type)
       #
       def _to_arguments(command, supported, opts = {})
         opts.inject(command) do |cmd, (flag, value)|
-          supported.include?(flag) ? (cmd << "-#{ flag }" << value.to_s) : cmd
+          supported.include?(flag) ? (cmd << "-#{flag}" << value.to_s) : cmd
         end
       end
     end
diff --git a/lib/notiffany/notifier/terminal_title.rb b/lib/notiffany/notifier/terminal_title.rb
index 2a96b96..7643f94 100644
--- a/lib/notiffany/notifier/terminal_title.rb
+++ b/lib/notiffany/notifier/terminal_title.rb
@@ -32,7 +32,7 @@ def _check_available(_options)
       def _perform_notify(message, opts = {})
         first_line = message.sub(/^\n/, "").sub(/\n.*/m, "")
 
-        STDOUT.puts "\e]2;[#{ opts[:title] }] #{ first_line }\a"
+        STDOUT.puts "\e]2;[#{opts[:title]}] #{first_line}\a"
       end
     end
   end
diff --git a/lib/notiffany/notifier/tmux.rb b/lib/notiffany/notifier/tmux.rb
index 9a25fe5..2023200 100644
--- a/lib/notiffany/notifier/tmux.rb
+++ b/lib/notiffany/notifier/tmux.rb
@@ -1,5 +1,8 @@
 require "notiffany/notifier/base"
-require "shellany/sheller"
+
+require "notiffany/notifier/tmux/client"
+require "notiffany/notifier/tmux/session"
+require "notiffany/notifier/tmux/notification"
 
 # TODO: this probably deserves a gem of it's own
 module Notiffany
@@ -27,134 +30,6 @@ class Tmux < Base
         color_location:         "status-left-bg"
       }
 
-      class Client
-        CLIENT = "tmux"
-
-        class << self
-          def version
-            Float(_capture("-V")[/\d+\.\d+/])
-          end
-
-          def _capture(*args)
-            Shellany::Sheller.stdout(([CLIENT] + args).join(" "))
-          end
-
-          def _run(*args)
-            Shellany::Sheller.run(([CLIENT] + args).join(" "))
-          end
-        end
-
-        def initialize(client)
-          @client = client
-        end
-
-        def clients
-          return [@client] unless @client == :all
-          ttys = _capture("list-clients", "-F", "'\#{client_tty}'")
-          ttys = ttys.split(/\n/)
-
-          # if user is running 'tmux -C' remove this client from list
-          ttys.delete("(null)")
-          ttys
-        end
-
-        def set(key, value)
-          clients.each do |client|
-            args = client ? ["-t", client.strip] : nil
-            _run("set", "-q", *args, key, value)
-          end
-        end
-
-        def display_message(message)
-          clients.each do |client|
-            args = ["-c", client.strip] if client
-            # TODO: should properly escape message here
-            _run("display", *args, "'#{message}'")
-          end
-        end
-
-        def unset(key, value)
-          clients.each do |client|
-            args = client ? ["-t", client.strip] : []
-            if value
-              _run("set", "-q", *args, key, value)
-            else
-              _run("set", "-q", "-u", *args, key)
-            end
-          end
-        end
-
-        def parse_options
-          output = _capture("show", "-t", @client)
-          Hash[output.lines.map { |line| _parse_option(line) }]
-        end
-
-        def message_fg=(color)
-          set("message-fg", color)
-        end
-
-        def message_bg=(color)
-          set("message-bg", color)
-        end
-
-        def display_time=(time)
-          set("display-time", time)
-        end
-
-        def title=(string)
-          # TODO: properly escape?
-          set("set-titles-string", "'#{string}'")
-        end
-
-        private
-
-        def _run(*args)
-          self.class._run(*args)
-        end
-
-        def _capture(*args)
-          self.class._capture(*args)
-        end
-
-        def _parse_option(line)
-          line.partition(" ").map(&:strip).reject(&:empty?)
-        end
-      end
-
-      class Session
-        def initialize
-          @options_store = {}
-
-          # NOTE: we are reading the settings of all clients
-          # - regardless of the :display_on_all_clients option
-
-          # Ideally, this should be done incrementally (e.g. if we start with
-          # "current" client and then override the :display_on_all_clients to
-          # true, only then the option store should be updated to contain
-          # settings of all clients
-          Client.new(:all).clients.each do |client|
-            @options_store[client] = {
-              "status-left-bg"  => nil,
-              "status-right-bg" => nil,
-              "status-left-fg"  => nil,
-              "status-right-fg" => nil,
-              "message-bg"      => nil,
-              "message-fg"      => nil,
-              "display-time"    => nil
-            }.merge(Client.new(client).parse_options)
-          end
-        end
-
-        def close
-          @options_store.each do |client, options|
-            options.each do |key, value|
-              Client.new(client).unset(key, value)
-            end
-          end
-          @options_store = nil
-        end
-      end
-
       class Error < RuntimeError
       end
 
@@ -226,129 +101,31 @@ def _check_available(opts = {})
       #   message on all tmux clients or not
       #
       def _perform_notify(message, options = {})
-        change_color = options[:change_color]
         locations = Array(options[:color_location])
-        display_the_title = options[:display_title]
-        display_message = options[:display_message]
         type  = options[:type].to_s
         title = options[:title]
 
-        if change_color
-          color = _tmux_color(type, options)
-          locations.each do |location|
-            Client.new(client(options)).set(location, color)
-          end
-        end
-
-        _display_title(type, title, message, options) if display_the_title
-
-        return unless display_message
-        _display_message(type, title, message, options)
-      end
-
-      # Displays a message in the title bar of the terminal.
-      #
-      # @param [String] title the notification title
-      # @param [String] message the notification message body
-      # @param [Hash] options additional notification library options
-      # @option options [String] success_message_format a string to use as
-      #   formatter for the success message.
-      # @option options [String] failed_message_format a string to use as
-      #   formatter for the failed message.
-      # @option options [String] pending_message_format a string to use as
-      #   formatter for the pending message.
-      # @option options [String] default_message_format a string to use as
-      #   formatter when no format per type is defined.
-      #
-      def _display_title(type, title, message, options = {})
-        format = "#{type}_title_format".to_sym
-        default_title_format = options[:default_title_format]
-        title_format   = options.fetch(format, default_title_format)
-        teaser_message = message.split("\n").first
-        display_title  = title_format % [title, teaser_message]
-
-        Client.new(client(options)).title = display_title
-      end
-
-      # Displays a message in the status bar of tmux.
-      #
-      # @param [String] type the notification type. Either 'success',
-      #   'pending', 'failed' or 'notify'
-      # @param [String] title the notification title
-      # @param [String] message the notification message body
-      # @param [Hash] options additional notification library options
-      # @option options [Integer] timeout the amount of seconds to show the
-      #   message in the status bar
-      # @option options [String] success_message_format a string to use as
-      #   formatter for the success message.
-      # @option options [String] failed_message_format a string to use as
-      #   formatter for the failed message.
-      # @option options [String] pending_message_format a string to use as
-      #   formatter for the pending message.
-      # @option options [String] default_message_format a string to use as
-      #   formatter when no format per type is defined.
-      # @option options [String] success_message_color the success notification
-      #   foreground color name.
-      # @option options [String] failed_message_color the failed notification
-      #   foreground color name.
-      # @option options [String] pending_message_color the pending notification
-      #   foreground color name.
-      # @option options [String] default_message_color a notification
-      #   foreground color to use when no color per type is defined.
-      # @option options [String] line_separator a string to use instead of a
-      #   line-break.
-      #
-      def _display_message(type, title, message, opts = {})
-        default_format = opts[:default_message_format]
-        default_color = opts[:default_message_color]
-        display_time = opts[:timeout]
-        separator = opts[:line_separator]
-
-        format = "#{type}_message_format".to_sym
-        message_format = opts.fetch(format, default_format)
-
-        color = "#{type}_message_color".to_sym
-        message_color = opts.fetch(color, default_color)
-
-        color = _tmux_color(type, opts)
-        formatted_message = message.split("\n").join(separator)
-        msg = message_format % [title, formatted_message]
-
-        cl = Client.new(client(opts))
-        cl.display_time = display_time * 1000
-        cl.message_fg = message_color
-        cl.message_bg = color
-        cl.display_message(msg)
-      end
-
-      # Get the Tmux color for the notification type.
-      # You can configure your own color by overwriting the defaults.
-      #
-      # @param [String] type the notification type
-      # @return [String] the name of the emacs color
-      #
-      def _tmux_color(type, opts = {})
-        type = type.to_sym
-        opts[type] || opts[:default]
+        tmux = Notification.new(type, options)
+        tmux.colorize(locations) if options[:change_color]
+        tmux.display_title(title, message) if options[:display_title]
+        tmux.display_message(title, message) if options[:display_message]
       end
 
-      def self._start_session
-        fail "Already turned on!" if @session
-        @session = Session.new
-      end
-
-      def self._end_session
-        fail "Already turned off!" unless @session || nil
-        @session.close
-        @session = nil
-      end
+      class << self
+        def _start_session
+          fail "Already turned on!" if @session
+          @session = Session.new
+        end
 
-      def self._session
-        @session
-      end
+        def _end_session
+          fail "Already turned off!" unless @session
+          @session.close
+          @session = nil
+        end
 
-      def client(options)
-        options[:display_on_all_clients] ? :all : nil
+        def _session
+          @session
+        end
       end
     end
   end
diff --git a/lib/notiffany/notifier/tmux/client.rb b/lib/notiffany/notifier/tmux/client.rb
new file mode 100644
index 0000000..e740783
--- /dev/null
+++ b/lib/notiffany/notifier/tmux/client.rb
@@ -0,0 +1,103 @@
+require "shellany/sheller"
+
+module Notiffany
+  class Notifier
+    class Tmux < Base
+      # Class for actually calling TMux to run commands
+      class Client
+        CLIENT = "tmux".freeze
+
+        class << self
+          def version
+            Float(_capture("-V")[/\d+\.\d+/])
+          end
+
+          def _capture(*args)
+            Shellany::Sheller.stdout(([CLIENT] + args).join(" "))
+          end
+
+          def _run(*args)
+            Shellany::Sheller.run(([CLIENT] + args).join(" "))
+          end
+        end
+
+        def initialize(client)
+          @client = client
+        end
+
+        def clients
+          return [@client] unless @client == :all
+          ttys = _capture("list-clients", "-F", "'\#{client_tty}'")
+          ttys = ttys.split(/\n/)
+
+          # if user is running 'tmux -C' remove this client from list
+          ttys.delete("(null)")
+          ttys
+        end
+
+        def set(key, value)
+          clients.each do |client|
+            args = client ? ["-t", client.strip] : nil
+            _run("set", "-q", *args, key, value)
+          end
+        end
+
+        def display_message(message)
+          clients.each do |client|
+            args = ["-c", client.strip] if client
+            # TODO: should properly escape message here
+            _run("display", *args, "'#{message}'")
+          end
+        end
+
+        def unset(key, value)
+          clients.each do |client|
+            _run(*_all_args_for(key, value, client))
+          end
+        end
+
+        def parse_options
+          output = _capture("show", "-t", @client)
+          Hash[output.lines.map { |line| _parse_option(line) }]
+        end
+
+        def message_fg=(color)
+          set("message-fg", color)
+        end
+
+        def message_bg=(color)
+          set("message-bg", color)
+        end
+
+        def display_time=(time)
+          set("display-time", time)
+        end
+
+        def title=(string)
+          # TODO: properly escape?
+          set("set-titles-string", "'#{string}'")
+        end
+
+        private
+
+        def _run(*args)
+          self.class._run(*args)
+        end
+
+        def _capture(*args)
+          self.class._capture(*args)
+        end
+
+        def _parse_option(line)
+          line.partition(" ").map(&:strip).reject(&:empty?)
+        end
+
+        def _all_args_for(key, value, client)
+          unset = value ? [] : %w(-u)
+          args = client ? ["-t", client.strip] : []
+          ["set", "-q", *unset, *args, key, *[value].compact]
+        end
+      end
+    end
+  end
+end
diff --git a/lib/notiffany/notifier/tmux/notification.rb b/lib/notiffany/notifier/tmux/notification.rb
new file mode 100644
index 0000000..711de80
--- /dev/null
+++ b/lib/notiffany/notifier/tmux/notification.rb
@@ -0,0 +1,62 @@
+module Notiffany
+  class Notifier
+    class Tmux < Base
+      # Wraps a notification with it's options
+      class Notification
+        def initialize(type, options)
+          @type = type
+          @options = options
+          @color = options[type.to_sym] || options[:default]
+          @separator = options[:line_separator]
+          @message_color = _value_for(:message_color)
+          @client = Client.new(options[:display_on_all_clients] ? :all : nil)
+        end
+
+        def display_title(title, message)
+          title_format = _value_for(:title_format)
+
+          teaser_message = message.split("\n").first
+          display_title = format(title_format, title, teaser_message)
+
+          client.title = display_title
+        end
+
+        def display_message(title, message)
+          message = _message_for(title, message)
+
+          client.display_time = options[:timeout] * 1000
+          client.message_fg = message_color
+          client.message_bg = color
+          client.display_message(message)
+        end
+
+        def colorize(locations)
+          locations.each do |location|
+            client.set(location, color)
+          end
+        end
+
+        private
+
+        attr_reader :type
+        attr_reader :options
+        attr_reader :color
+        attr_reader :message_color
+        attr_reader :client
+        attr_reader :separator
+
+        def _value_for(field)
+          format = "#{type}_#{field}".to_sym
+          default = options["default_#{field}".to_sym]
+          options.fetch(format, default)
+        end
+
+        def _message_for(title, message)
+          message_format = _value_for(:message_format)
+          formatted_message = message.split("\n").join(separator)
+          format(message_format, title, formatted_message)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/notiffany/notifier/tmux/session.rb b/lib/notiffany/notifier/tmux/session.rb
new file mode 100644
index 0000000..bf7eb2b
--- /dev/null
+++ b/lib/notiffany/notifier/tmux/session.rb
@@ -0,0 +1,40 @@
+module Notiffany
+  class Notifier
+    class Tmux < Base
+      # Preserves TMux settings for all tmux sessions
+      class Session
+        def initialize
+          @options_store = {}
+
+          # NOTE: we are reading the settings of all clients
+          # - regardless of the :display_on_all_clients option
+
+          # Ideally, this should be done incrementally (e.g. if we start with
+          # "current" client and then override the :display_on_all_clients to
+          # true, only then the option store should be updated to contain
+          # settings of all clients
+          Client.new(:all).clients.each do |client|
+            @options_store[client] = {
+              "status-left-bg"  => nil,
+              "status-right-bg" => nil,
+              "status-left-fg"  => nil,
+              "status-right-fg" => nil,
+              "message-bg"      => nil,
+              "message-fg"      => nil,
+              "display-time"    => nil
+            }.merge(Client.new(client).parse_options)
+          end
+        end
+
+        def close
+          @options_store.each do |client, options|
+            options.each do |key, value|
+              Client.new(client).unset(key, value)
+            end
+          end
+          @options_store = nil
+        end
+      end
+    end
+  end
+end
diff --git a/notiffany.gemspec b/notiffany.gemspec
index 1d7d1cf..e805681 100644
--- a/notiffany.gemspec
+++ b/notiffany.gemspec
@@ -6,10 +6,14 @@ require 'notiffany/version'
 Gem::Specification.new do |spec|
   spec.name          = "notiffany"
   spec.version       = Notiffany::VERSION
-  spec.authors       = ["Cezary Baginski", "Rémy Coutable", "Thibaud Guillaume-Gentil"]
+  spec.authors       = [
+    "Cezary Baginski",
+    "Rémy Coutable",
+    "Thibaud Guillaume-Gentil"
+  ]
   spec.email         = ["cezary@chronomantic.net"]
 
-  spec.summary       = %q{Notifier library (extracted from Guard project)}
+  spec.summary       = 'Notifier library (extracted from Guard project)'
   spec.description   = <<-EOF
     Wrapper libray for most popular notification
     libraries such as Growl, Libnotify, Notifu
@@ -19,7 +23,7 @@ Gem::Specification.new do |spec|
   spec.license       = "MIT"
 
   git_files = `git ls-files -z`.split("\x0")
-  files = git_files.select { |f| /^lib\/.*$/ =~ f }
+  files = git_files.select { |f| %r{^lib/.*$} =~ f }
   files += %w(README.md LICENSE.txt)
 
   # skip the large images/guard.png
diff --git a/spec/lib/notiffany/notifier/base_spec.rb b/spec/lib/notiffany/notifier/base_spec.rb
index 18e067d..e9546b7 100644
--- a/spec/lib/notiffany/notifier/base_spec.rb
+++ b/spec/lib/notiffany/notifier/base_spec.rb
@@ -3,7 +3,7 @@
 # TODO: no point in testing the base class, really
 module Notiffany
   RSpec.describe Notifier::Base do
-    let(:fake) { double ("fake_lib") }
+    let(:fake) { double "fake_lib" }
     let(:options) { {} }
     let(:os) { "solaris" }
 
diff --git a/spec/lib/notiffany/notifier/detected_spec.rb b/spec/lib/notiffany/notifier/detected_spec.rb
index 2ee4b7e..dd3c3da 100644
--- a/spec/lib/notiffany/notifier/detected_spec.rb
+++ b/spec/lib/notiffany/notifier/detected_spec.rb
@@ -5,7 +5,6 @@ class Notifier
     RSpec.describe YamlEnvStorage do
       let(:subject) { YamlEnvStorage.new("notiffany_tests_foo") }
       describe "#notifiers" do
-
         context "when set to empty array" do
           before { subject.notifiers = [] }
           specify { expect(subject.notifiers).to be_empty }
@@ -51,7 +50,7 @@ class Notifier
         end
       end
 
-      describe ".available" do
+      describe "#available" do
         context "with detected notifiers" do
           let(:available) do
             [
@@ -74,11 +73,13 @@ class Notifier
         end
       end
 
-      describe ".add" do
+      describe "#add" do
         before do
-          allow(env).to receive(:notifiers).and_return([])
+          allow(env).to receive(:notifiers).and_return(notifiers)
         end
+
         context "with no detected notifiers" do
+          let(:notifiers) { [] }
           context "when unknown" do
             it "does not add the library" do
               expect(env).to_not receive(:notifiers=)
@@ -87,9 +88,37 @@ class Notifier
             end
           end
         end
+
+        context "with manually configured notifiers" do
+          let(:notifiers) { [] }
+
+          context "when not available" do
+            before do
+              allow(foo_mod).to receive(:new).
+                with(foo: :bar).
+                and_raise(Notifier::Base::UnavailableError, "something failed")
+              allow(logger).to receive(:warning)
+            end
+
+            it "does not add the library" do
+              expect(env).to_not receive(:notifiers=)
+              subject.add(:foo, foo: :bar)
+            end
+
+            it "does not raise an error" do
+              expect { subject.add(:foo, foo: :bar) }.to_not raise_error
+            end
+
+            it "shows a warning" do
+              expect(logger).to receive(:warning).
+                with("Notiffany: foo not available (something failed).")
+              subject.add(:foo, foo: :bar)
+            end
+          end
+        end
       end
 
-      describe ".detect" do
+      describe "#detect" do
         context "with some detected notifiers" do
           before do
             allow(env).to receive(:notifiers).and_return([])
@@ -127,7 +156,7 @@ class Notifier
         end
       end
 
-      describe ".reset" do
+      describe "#reset" do
         before do
           allow(env).to receive(:notifiers=)
         end
diff --git a/spec/lib/notiffany/notifier/growl_spec.rb b/spec/lib/notiffany/notifier/growl_spec.rb
index e787bb6..bb11ec8 100644
--- a/spec/lib/notiffany/notifier/growl_spec.rb
+++ b/spec/lib/notiffany/notifier/growl_spec.rb
@@ -3,7 +3,7 @@
 module Notiffany
   RSpec.describe Notifier::Growl do
     module FakeGrowl
-      def self.notify(message, opts)
+      def self.notify(_message, _opts)
       end
 
       def self.installed?
@@ -67,11 +67,11 @@ def self.switches
           expect(growl).to receive(:notify).with(
             "Welcome!",
             hash_including(
-            sticky:   false,
-            priority: 0,
-            name:     "Notiffany",
-            title:    "Hello",
-            image:    "/tmp/welcome.png"
+              sticky:   false,
+              priority: 0,
+              name:     "Notiffany",
+              title:    "Hello",
+              image:    "/tmp/welcome.png"
             )
           )
 
@@ -82,12 +82,12 @@ def self.switches
           expect(growl).to receive(:notify).with(
             "Welcome!",
             hash_including(
-            sticky:   false,
-            priority: 0,
-            name:     "Notiffany",
-            title:    "Welcome",
-            image:    "/tmp/welcome.png"
-          )
+              sticky:   false,
+              priority: 0,
+              name:     "Notiffany",
+              title:    "Welcome",
+              image:    "/tmp/welcome.png"
+            )
           )
 
           subject.notify("Welcome!",
@@ -101,11 +101,11 @@ def self.switches
           expect(growl).to receive(:notify).with(
             "Welcome!",
             hash_including(
-            sticky:   false,
-            priority: 0,
-            name:     "Notiffany",
-            title:    "Welcome",
-            image:    "/tmp/welcome.png"
+              sticky:   false,
+              priority: 0,
+              name:     "Notiffany",
+              title:    "Welcome",
+              image:    "/tmp/welcome.png"
             )
           )
 
@@ -121,12 +121,12 @@ def self.switches
           expect(growl).to receive(:notify).with(
             "Waiting for something",
             hash_including(
-            sticky:   true,
-            priority: 2,
-            name:     "Notiffany",
-            title:    "Waiting",
-            image:    "/tmp/wait.png"
-          )
+              sticky:   true,
+              priority: 2,
+              name:     "Notiffany",
+              title:    "Waiting",
+              image:    "/tmp/wait.png"
+            )
           )
 
           subject.notify(
diff --git a/spec/lib/notiffany/notifier/notifysend_spec.rb b/spec/lib/notiffany/notifier/notifysend_spec.rb
index e3a813f..55b97d7 100644
--- a/spec/lib/notiffany/notifier/notifysend_spec.rb
+++ b/spec/lib/notiffany/notifier/notifysend_spec.rb
@@ -34,7 +34,7 @@ class Notifier
 
           it "checks if the binary is available" do
             expect(sheller).to receive(:stdout).with("which notify-send").
-                                       and_return("foo\n")
+              and_return("foo\n")
             subject
           end
         end
diff --git a/spec/lib/notiffany/notifier/rb_notifu_spec.rb b/spec/lib/notiffany/notifier/rb_notifu_spec.rb
index 739570f..e4197e4 100644
--- a/spec/lib/notiffany/notifier/rb_notifu_spec.rb
+++ b/spec/lib/notiffany/notifier/rb_notifu_spec.rb
@@ -126,7 +126,6 @@ class Notifier
           end
         end
       end
-
     end
   end
 end
diff --git a/spec/lib/notiffany/notifier/terminal_notifier_spec.rb b/spec/lib/notiffany/notifier/terminal_notifier_spec.rb
index 56f7819..330b84f 100644
--- a/spec/lib/notiffany/notifier/terminal_notifier_spec.rb
+++ b/spec/lib/notiffany/notifier/terminal_notifier_spec.rb
@@ -88,6 +88,5 @@ module Notiffany
         end
       end
     end
-
   end
 end
diff --git a/spec/lib/notiffany/notifier/tmux_spec.rb b/spec/lib/notiffany/notifier/tmux_spec.rb
index f23a188..dfe63c2 100644
--- a/spec/lib/notiffany/notifier/tmux_spec.rb
+++ b/spec/lib/notiffany/notifier/tmux_spec.rb
@@ -45,7 +45,8 @@ class Notifier
               "/dev/ttys001\n"
             end
 
-            expect(sheller).to receive(:run).with("tmux display -c /dev/ttys001 'foo'")
+            expect(sheller).to receive(:run)
+              .with("tmux display -c /dev/ttys001 'foo'")
             subject.display_message("foo")
           end
         end
@@ -153,9 +154,7 @@ class Notifier
       end
 
       after do
-        if described_class.send(:_session)
-          described_class.send(:_end_session)
-        end
+        described_class.send(:_end_session) if described_class.send(:_session)
       end
 
       describe "#initialize" do
@@ -176,7 +175,7 @@ class Notifier
                 to raise_error(
                   Base::UnavailableError,
                   /way too old \(1.6\)/
-              )
+                )
             end
           end
         end
@@ -188,7 +187,7 @@ class Notifier
               to raise_error(
                 Base::UnavailableError,
                 /only available inside a TMux session/
-            )
+              )
           end
         end
       end
@@ -470,7 +469,7 @@ class Notifier
             {
               type: "pending",
               title: "any title",
-              display_message: true,
+              display_message: true
             }
           end
 
diff --git a/spec/lib/notiffany/notifier_spec.rb b/spec/lib/notiffany/notifier_spec.rb
index e94071b..b563049 100644
--- a/spec/lib/notiffany/notifier_spec.rb
+++ b/spec/lib/notiffany/notifier_spec.rb
@@ -13,7 +13,7 @@ module Notiffany
       let(name.to_sym) do
         class_double(
           "Notiffany::Notifier::Tmux",
-          name: name,
+          name: name
         )
       end
     end
@@ -109,8 +109,8 @@ module Notiffany
 
       context "with custom notifier config" do
         let(:env_enabled) { true }
-        let(:notifiers) { {foo: { bar: :baz} } }
-        let(:options) { { notifiers: notifiers} }
+        let(:notifiers) { { foo: { bar: :baz } } }
+        let(:options) { { notifiers: notifiers } }
 
         before do
           allow(detected).to receive(:available).and_return([])