diff --git a/rake/pkg/rbenv.rake b/rake/pkg/rbenv.rake
index 48433f22..5ab002bc 100644
--- a/rake/pkg/rbenv.rake
+++ b/rake/pkg/rbenv.rake
@@ -1,11 +1,12 @@
-RBENV_ROOT = File.expand_path("~/.rbenv")
+RBENV_ROOT = File.expand_path('~/.rbenv')
 
 def rbenv_installed?
-  Dir.exists?(RBENV_ROOT)
+  Dir.exist?(RBENV_ROOT)
 end
 
 def rbenv_versions
-  `ls -1 #{RBENV_ROOT}/versions`.split("\n") if Dir.exists? "#{RBENV_ROOT}/versions"
+  return [] unless Dir.exist? "#{RBENV_ROOT}/versions"
+  `ls -1 #{RBENV_ROOT}/versions`.split("\n")
 end
 
 def rbenv_plugins
@@ -14,7 +15,6 @@ end
 
 def rbenv_set_default_gems(*gems)
   default_gems_file = "#{RBENV_ROOT}/default-gems"
-  return if !gems.is_a?(Array) or gems.length == 0 or File.exists?(default_gems_file)
   File.write(default_gems_file, gems.join("\n"))
 end
 
@@ -24,31 +24,31 @@ end
 
 ###
 
-desc "Install/update rbenv & all rubies"
-task :rbenv => 'rbenv:update'
+desc 'Install/update rbenv & all rubies'
+task rbenv: 'rbenv:update'
 
 namespace :rbenv do
   task :install do
     unless rbenv_installed?
-      echo "Installing rbenv"
-      github "sstephenson/rbenv", RBENV_ROOT
+      echo 'Installing rbenv'
+      github 'sstephenson/rbenv', RBENV_ROOT
 
       mkdir_p "#{RBENV_ROOT}/plugins"
-      [ "sstephenson/rbenv-vars",
-        "sstephenson/ruby-build",
-        "sstephenson/rbenv-default-gems",
-        "sstephenson/rbenv-gem-rehash",
-        "fesplugas/rbenv-installer",
-        "fesplugas/rbenv-bootstrap",
-        "rkh/rbenv-update",
-        "rkh/rbenv-whatis",
-        "rkh/rbenv-use"
+      ['sstephenson/rbenv-vars',
+       'sstephenson/ruby-build',
+       'sstephenson/rbenv-default-gems',
+       'sstephenson/rbenv-gem-rehash',
+       'fesplugas/rbenv-installer',
+       'fesplugas/rbenv-bootstrap',
+       'rkh/rbenv-update',
+       'rkh/rbenv-whatis',
+       'rkh/rbenv-use'
       ].each do |pkg|
         echo "Installing #{pkg}", 2
-        github pkg, "#{RBENV_ROOT}/plugins/#{pkg.split("/")[1]}"
+        github pkg, "#{RBENV_ROOT}/plugins/#{pkg.split('/')[1]}"
       end
 
-      echo "Initializing rbenv", 2
+      echo 'Initializing rbenv', 2
       sh_safe "eval \"$(#{RBENV_ROOT}/bin/rbenv init -)\""
     end
 
@@ -56,18 +56,18 @@ namespace :rbenv do
     rbenv_set_default_gems(
       'bundler',
       'rspec',
+      'doing',
       'pry',
       'pry-doc',
-      'factory_girl',
-      'guard',
-      'rb-fsevent',
-      'guard-livereload',
-      'guard-sass',
-      'guard-concat'
+      'pry-byebug',
+      'pry-rescue',
+      'pry-stack_explorer',
+      'ripper-tags',
+      'gem-ripper-tags'
     )
 
     # Install global ruby + gems
-    ruby_version = "2.1.2"
+    ruby_version = '2.1.3'
     unless rbenv_version_installed? ruby_version
       echo "Setting up default ruby (#{ruby_version})", 2
       sh_safe "rbenv install #{ruby_version}"
@@ -76,27 +76,27 @@ namespace :rbenv do
     end
   end
 
-  task :update => "rbenv:install" do
-    echo "Updating rbenv & plugins"
-    sh_safe "rbenv update"
+  task update: 'rbenv:install' do
+    echo 'Updating rbenv & plugins'
+    sh_safe 'rbenv update'
 
     rbenv_versions.each do |version|
       echo "Updating ruby #{version}"
 
       cmd = "#{RBENV_ROOT}/shims/gem"
-      cmd = "sudo #{cmd}" if version == "system"
+      cmd = "sudo #{cmd}" if version == 'system'
 
       sh_safe "RBENV_VERSION=#{version} #{cmd} update --system -f"
       sh_safe "RBENV_VERSION=#{version} #{cmd} update -f"
       sh_safe "RBENV_VERSION=#{version} #{cmd} clean"
     end
 
-    sh_safe "rbenv rehash"
+    sh_safe 'rbenv rehash'
   end
 
   if rbenv_installed?
     task :remove do
-      echo "Deleting rbenv"
+      echo 'Deleting rbenv'
       sh_safe "rm -rf #{RBENV_ROOT}"
     end
   end
diff --git a/zshrc b/zshrc
index d919aedf..8692c25c 100644
--- a/zshrc
+++ b/zshrc
@@ -14,7 +14,9 @@ source ~/.zsh/aliases
 
 # Initialize rbenv and pyenv; rehashing slows down zsh startup, so we
 # disable it.
-is-callable 'rbenv' && eval "$(rbenv init - --no-rehash)"
+if is-callable 'rbenv'; then
+    eval "$(rbenv init - --no-rehash)"
+fi
 if is-callable 'pyenv'; then
     eval "$(pyenv init - --no-rehash)"
     eval "$(pyenv virtualenv-init -)"