diff --git a/install.sh b/install.sh
index 69465e9..a76a694 100755
--- a/install.sh
+++ b/install.sh
@@ -32,8 +32,10 @@ SYMLINKS=(
   rubocop.yml
   tmux
   tmux.conf
+  zshenv
+  zshrc
 )
-LOAD_FILES=(zshrc)
+LOAD_FILES=()
 
 
 #
@@ -67,11 +69,6 @@ install_symlinks () {
   for i in "${SYMLINKS[@]}"; do
     symlink "$SYMLINK_PATH/$i" "$TARGET/.$i"
   done
-
-  # Symlink shell init file for bash and zsh
-  for i in "${LOAD_FILES[@]}"; do
-    symlink "$DOTFILES_LINK/load_shellrc.sh" "$TARGET/.$i"
-  done
 }
 
 install_private () {
diff --git a/load_shellrc.sh b/load_shellrc.sh
deleted file mode 100644
index 11e8f70..0000000
--- a/load_shellrc.sh
+++ /dev/null
@@ -1 +0,0 @@
-source "$HOME/.dotfiles/zshrc.zsh"
diff --git a/zsh/aliases.zsh b/zsh/aliases.zsh
index 658cc2f..71c2a85 100644
--- a/zsh/aliases.zsh
+++ b/zsh/aliases.zsh
@@ -27,6 +27,20 @@ alias di="colordiff"
 alias devnullsmtp="java -jar $DOTBIN/DevNullSmtp.jar"
 alias open_ports="sudo lsof -i -P | grep --color=never -i \"listen\""
 
+# Homebrew
+if (( $+commands[brew] )); then
+  alias br="brew"
+  alias ca="brew cask"
+  alias cask="brew cask"
+  alias bb="brew bundle"
+  alias bbg="brew bundle --global"
+fi
+
+# Flutter
+if (( $+commands[flutter] )); then
+  alias fl="flutter"
+fi
+
 # Flush DNS cache
 alias flush_dns="dscacheutil -flushcache"
 
diff --git a/zsh/android-sdk.zsh b/zsh/android-sdk.zsh
deleted file mode 100644
index 4526d51..0000000
--- a/zsh/android-sdk.zsh
+++ /dev/null
@@ -1,11 +0,0 @@
-#
-# Android SDK environment setup.
-#
-
-if [ -d "$HOME/Library/Android/sdk" ]; then
-  export ANDROID_HOME="$HOME/Library/Android/sdk"
-  path_append "$ANDROID_HOME/emulator"
-  path_append "$ANDROID_HOME/tools"
-  path_append "$ANDROID_HOME/tools/bin"
-  path_append "$ANDROID_HOME/platform-tools"
-fi
diff --git a/zsh/docker.zsh b/zsh/docker.zsh
index 2c93173..bba8492 100644
--- a/zsh/docker.zsh
+++ b/zsh/docker.zsh
@@ -7,5 +7,5 @@ alias dc="docker-compose"
 alias co="docker-compose"
 
 docker_remove_exited () {
-  docker rm $(docker ps -f="status=exited" -q)
+  docker rm "$(docker ps -f='status=exited' -q)"
 }
diff --git a/zsh/emacs.zsh b/zsh/emacs.zsh
index 5160b6f..ff73b12 100644
--- a/zsh/emacs.zsh
+++ b/zsh/emacs.zsh
@@ -2,7 +2,7 @@
 # Emacs
 #
 
-# OS X systems.
+# macOS systems
 if [ -f "/Applications/Emacs.app/Contents/MacOS/Emacs" ]; then
   alias emacs="env TERM=screen-24bit /Applications/Emacs.app/Contents/MacOS/Emacs -nw"
 fi
@@ -10,8 +10,3 @@ fi
 if [ -f "/Applications/Emacs.app/Contents/MacOS/bin/emacsclient" ]; then
   alias emacsclient="env TERM=screen-24bit /Applications/Emacs.app/Contents/MacOS/bin/emacsclient"
 fi
-
-# *nix systems.
-if [ -d "/opt/emacs/bin" ]; then
-  path_append "/opt/emacs/bin"
-fi
diff --git a/zsh/flutter.zsh b/zsh/flutter.zsh
deleted file mode 100644
index 73cec75..0000000
--- a/zsh/flutter.zsh
+++ /dev/null
@@ -1,12 +0,0 @@
-#
-# Flutter environment setup
-#
-
-if [ -d "/opt/flutter/bin" ]; then
-  path_append "/opt/flutter/bin"
-  alias fl="flutter"
-
-  if [ -d "/opt/flutter/bin/cache/dart-sdk/bin" ]; then
-    path_append "/opt/flutter/bin/cache/dart-sdk/bin"
-  fi
-fi
diff --git a/zsh/gnu-getopt.zsh b/zsh/gnu-getopt.zsh
deleted file mode 100644
index e819395..0000000
--- a/zsh/gnu-getopt.zsh
+++ /dev/null
@@ -1,7 +0,0 @@
-#
-# Use gnu-getopt if it's available
-#
-
-if [ -f "/usr/local/opt/gnu-getopt/bin/getopt" ]; then
-  path_prepend "/usr/local/opt/gnu-getopt/bin"
-fi
diff --git a/zsh/golang.zsh b/zsh/golang.zsh
index 1c83732..54130c5 100755
--- a/zsh/golang.zsh
+++ b/zsh/golang.zsh
@@ -1,10 +1,7 @@
 #
-# Go (golang) environment setup.
+# Go (golang) setup.
 #
 
-export GOPATH="$HOME/.go"
-path_prepend "$GOPATH/bin"
-
 install_go_global_packages () {
   local packages=(
     github.com/akavel/up
diff --git a/zsh/homebrew.zsh b/zsh/homebrew.zsh
deleted file mode 100644
index 67f6459..0000000
--- a/zsh/homebrew.zsh
+++ /dev/null
@@ -1,12 +0,0 @@
-#
-# Homebrew setup.
-#
-
-export HOMEBREW_NO_ANALYTICS=1
-
-# Aliases
-alias br="brew"
-alias ca="brew cask"
-alias cask="brew cask"
-alias bb="brew bundle"
-alias bbg="brew bundle --global"
diff --git a/zsh/kubernetes.zsh b/zsh/kubernetes.zsh
index 22b30c0..c02b876 100644
--- a/zsh/kubernetes.zsh
+++ b/zsh/kubernetes.zsh
@@ -6,8 +6,6 @@ alias kc="kubectl"
 alias hl="helm"
 alias mk="minikube"
 
-export KUBECONFIG="$HOME/.kube/config:.kube/config"
-
-if [ $commands[kubectl] ]; then
+if (( $+commands[kubectl] )); then
   eval "$(kubectl completion zsh)"
 fi
diff --git a/zsh/less.zsh b/zsh/less.zsh
index 4dbc28d..6e66b41 100644
--- a/zsh/less.zsh
+++ b/zsh/less.zsh
@@ -5,7 +5,7 @@
 alias le="less"
 
 # Enable syntax highlighting via source-highlight
-if [ $commands[src-hilite-lesspipe.sh] ]; then
+if (( $+commands[src-hilite-lesspipe.sh] )); then
   export LESSOPEN="| src-hilite-lesspipe.sh %s"
   export LESS=" -R "
 fi
diff --git a/zsh/macos.zsh b/zsh/macos.zsh
new file mode 100644
index 0000000..ef05648
--- /dev/null
+++ b/zsh/macos.zsh
@@ -0,0 +1,55 @@
+#
+# macOS Specific
+#
+
+# Fix wifi issues on OS X 10.10.x Yosemite.
+#  - from: https://medium.com/@mariociabarra/wifried-ios-8-wifi-performance-issues-3029a164ce94
+alias fix_wifi="sudo ifconfig awdl0 down"
+alias unfix_wifi="sudo ifconfig awdl0 up"
+
+# Disable the system built-in cmd+ctrl+d global hotkey to lookup word in
+# dictionary on OS X. Must reboot after running.
+#  - from: ://apple.stackexchange.com/a/114269
+osx-disable-lookup-word-hotkey () {
+  defaults write com.apple.symbolichotkeys AppleSymbolicHotKeys -dict-add 70 \
+           '<dict><key>enabled</key><false/></dict>'
+  echo "Command-Control-D hotkey disabled. Please reboot to take effect."
+}
+
+#
+# Power management
+#
+
+# Set all relevant power management settings to force the machine to save a
+# sleep image and immediately enter "standby" along with FileVault destroying
+# disk decryption keys.
+pm-hibernate () {
+  sudo pmset -a hibernatemode 25
+  sudo pmset -a standby 1
+  sudo pmset -a standbydelayhigh 0
+  sudo pmset -a standbydelaylow 0
+  sudo pmset -a autopoweroffdelay 0
+  sudo pmset -a destroyfvkeyonstandby 1
+}
+
+# Restore all settings modified by pm-hibernate to their defaults, effectively
+# restoring default sleep behavior for macOS laptops.
+pm-safesleep () {
+  sudo pmset -a hibernatemode 3
+  sudo pmset -a standbydelayhigh 86400
+  sudo pmset -a standbydelaylow 0
+  sudo pmset -a autopoweroffdelay 28800
+  sudo pmset -a destroyfvkeyonstandby 0
+}
+
+# Trigger hibernation now.
+hibernate () {
+  pm-hibernate
+  sudo pmset sleepnow
+}
+
+# Trigger a safe-sleep now.
+safesleep () {
+  pm-safesleep
+  sudo pmset sleepnow
+}
diff --git a/zsh/nodejs.zsh b/zsh/nodejs.zsh
index 60bf938..570d66c 100755
--- a/zsh/nodejs.zsh
+++ b/zsh/nodejs.zsh
@@ -40,8 +40,3 @@ install_node_global_packages () {
 
   npm install -g "${packages[@]}"
 }
-
-# Load nvm if it's available
-if [ -f "$HOME/.nvm/nvm.sh" ]; then
-  source "$HOME/.nvm/nvm.sh"
-fi
diff --git a/zsh/osx.zsh b/zsh/osx.zsh
deleted file mode 100644
index 7de968a..0000000
--- a/zsh/osx.zsh
+++ /dev/null
@@ -1,69 +0,0 @@
-#
-# OSX Related
-#
-
-if [[ "$(uname)" == "Darwin" ]]; then
-  # Fix wifi issues on OS X 10.10.x Yosemite.
-  #  - from: https://medium.com/@mariociabarra/wifried-ios-8-wifi-performance-issues-3029a164ce94
-  alias fix_wifi="sudo ifconfig awdl0 down"
-  alias unfix_wifi="sudo ifconfig awdl0 up"
-
-  # Disable the system built-in cmd+ctrl+d global hotkey to lookup word in
-  # dictionary on OS X. Must reboot after running.
-  #  - from: ://apple.stackexchange.com/a/114269
-  osx-disable-lookup-word-hotkey() {
-    defaults write com.apple.symbolichotkeys AppleSymbolicHotKeys -dict-add 70 \
-             '<dict><key>enabled</key><false/></dict>'
-    echo "Command-Control-D hotkey disabled. Please reboot to take effect."
-  }
-
-  # Show hidden files in Finder.
-  show_files() {
-    defaults write com.apple.finder AppleShowAllFiles YES
-    killall Finder "/System/Library/CoreServices/Finder.app"
-  }
-
-  # Don't show hidden files in Finder.
-  hide_files() {
-    defaults write com.apple.finder AppleShowAllFiles NO
-    killall Finder "/System/Library/CoreServices/Finder.app"
-  }
-
-  #
-  # Power management
-  #
-
-  # Set all relevant power management settings to force the machine to save a
-  # sleep image and immediately enter "standby" along with FileVault destroying
-  # disk decryption keys.
-  pm-hibernate() {
-    sudo pmset -a hibernatemode 25
-    sudo pmset -a standby 1
-    sudo pmset -a standbydelayhigh 0
-    sudo pmset -a standbydelaylow 0
-    sudo pmset -a autopoweroffdelay 0
-    sudo pmset -a destroyfvkeyonstandby 1
-  }
-
-  # Restore all settings modified by pm-hibernate to their defaults, effectively
-  # restoring default sleep behavior for macOS laptops.
-  pm-safesleep() {
-    sudo pmset -a hibernatemode 3
-    sudo pmset -a standbydelayhigh 86400
-    sudo pmset -a standbydelaylow 0
-    sudo pmset -a autopoweroffdelay 28800
-    sudo pmset -a destroyfvkeyonstandby 0
-  }
-
-  # Trigger hibernation now.
-  hibernate() {
-    pm-hibernate
-    sudo pmset sleepnow
-  }
-
-  # Trigger a safe-sleep now.
-  safesleep() {
-    pm-safesleep
-    sudo pmset sleepnow
-  }
-fi
diff --git a/zsh/ruby.zsh b/zsh/ruby.zsh
index d02df35..6639f22 100755
--- a/zsh/ruby.zsh
+++ b/zsh/ruby.zsh
@@ -40,6 +40,7 @@ alias scu="RAILS_ENV=cucumber bundle exec spring cucumber"
 alias va="vagrant"
 
 # Bundler aliases
+alias bch="bundle check"
 alias bcn="bundle clean"
 alias bco="bundle console"
 alias be="bundle exec"
@@ -50,10 +51,6 @@ alias bp="bundle package"
 alias bu="bundle update"
 
 # lazy-load rbenv
-if [ -d "$HOME/.rbenv/shims" ]; then
-  path_prepend "$HOME/.rbenv/shims"
-fi
-
 rbenv() {
   eval "$(command rbenv init -)"
   rbenv "$@"
diff --git a/zsh/rust.zsh b/zsh/rust.zsh
index 473f360..ee9956e 100644
--- a/zsh/rust.zsh
+++ b/zsh/rust.zsh
@@ -2,11 +2,6 @@
 # Rust environment setup.
 #
 
-# Rustup
-if [ -d "$HOME/.cargo/bin" ]; then
-  path_prepend "$HOME/.cargo/bin"
-fi
-
 install_rust_global_packages() {
   local packages=(
     rls
diff --git a/zsh/tmux.zsh b/zsh/tmux.zsh
index 1ce80f6..0f10d78 100644
--- a/zsh/tmux.zsh
+++ b/zsh/tmux.zsh
@@ -5,11 +5,6 @@ alias tmn="tm new"
 alias tml="tm ls"
 alias tmm="tmn -s main"
 
-# Custom Install
-if [ -d "/opt/tmux/bin" ]; then
-  path_prepend "/opt/tmux/bin"
-fi
-
 # Tmux Completion
 if [ -f "/usr/local/etc/bash_completion.d/tmux" ]; then
   source "/usr/local/etc/bash_completion.d/tmux"
diff --git a/zshenv b/zshenv
new file mode 100644
index 0000000..64db438
--- /dev/null
+++ b/zshenv
@@ -0,0 +1,125 @@
+#
+# ZSH Environment Setup
+#
+
+# Ensure values in path variable are unique.
+typeset -U path
+
+# Path helpers
+path_list () {
+  print -l "${(@)path}"
+}
+
+path_remove () {
+  path=("${(@)path:#$1}")
+}
+
+path_append () {
+  if [ -d "$1" ]; then
+    path+="$1"
+  fi
+}
+
+path_prepend () {
+  if [ -d "$1" ]; then
+    path=("$1" "${(@)path:#$1}")
+  fi
+}
+
+
+# ==============================================================================
+# System Environment Setup
+# ==============================================================================
+
+DOTFILES="$HOME/.dotfiles"
+DOTBIN="$DOTFILES/bin"
+DOTZSH="$DOTFILES/zsh"
+
+# Editors
+export EDITOR="emacsclient-wrapper"
+export GEM_EDITOR="mate"
+
+# Locale Setup
+export LC_ALL="en_US.UTF-8"
+export LANG="en_US.UTF-8"
+
+# Ensure TMPDIR is the same for local and remote ssh logins
+if [[ "$TMPDIR" == "/var/folders/"* ]] || [[ "$TMPDIR" == "" ]]; then
+  export TMPDIR="/tmp/user-$USER"
+  mkdir -p "$TMPDIR"
+fi
+
+# Ensure basic systems paths are in desired order.
+path_prepend "/sbin"
+path_prepend "/bin"
+path_prepend "/usr/sbin"
+path_prepend "/usr/bin"
+path_prepend "/usr/local/sbin"
+path_prepend "/usr/local/bin"
+
+# Add dotfiles' bin directory to PATH
+path_prepend "$DOTBIN"
+
+# Add user's bin directory to PATH
+path_prepend "$HOME/bin"
+
+
+# ==============================================================================
+# Private Dotfiles Environment
+# ==============================================================================
+
+DOTPFILES="$DOTFILES/private"
+
+if [ -f "$DOTPFILES/zshenv" ]; then
+  source "$DOTPFILES/zshenv"
+fi
+
+# ==============================================================================
+# Third-party Environment Setup
+# ==============================================================================
+
+# Android SDK environment setup.
+if [ -d "$HOME/Library/Android/sdk" ]; then
+  export ANDROID_HOME="$HOME/Library/Android/sdk"
+  path_append "$ANDROID_HOME/emulator"
+  path_append "$ANDROID_HOME/tools"
+  path_append "$ANDROID_HOME/tools/bin"
+  path_append "$ANDROID_HOME/platform-tools"
+fi
+
+# Flutter environment setup
+path_append "/opt/flutter/bin"
+path_append "/opt/flutter/bin/cache/dart-sdk/bin"
+
+# Use gnu-getop if available
+path_prepend "/usr/local/opt/gnu-getopt/bin"
+
+# Go (golang) environment setup
+export GOPATH="$HOME/.go"
+path_prepend "$GOPATH/bin"
+
+# Homebrew setup
+export HOMEBREW_NO_ANALYTICS=1
+
+# Kubernetes setup
+export KUBECONFIG="$HOME/.kube/config:.kube/config"
+
+# Use custom emacs install if available
+path_prepend "/opt/emacs/bin"
+
+# Use custom tmux install if available
+path_prepend "/opt/tmux/bin"
+
+# Ruby setup
+path_prepend "$HOME/.rbenv/shims"
+
+# Rust setup
+path_prepend "$HOME/.cargo/bin"
+
+# ==============================================================================
+# Local Overrides
+# ==============================================================================
+
+if [ -f "$HOME/.zshenv.local" ]; then
+  source "$HOME/.zshenv.local"
+fi
diff --git a/zshrc.zsh b/zshrc
similarity index 67%
rename from zshrc.zsh
rename to zshrc
index 8533952..3a9c34e 100644
--- a/zshrc.zsh
+++ b/zshrc
@@ -2,52 +2,11 @@
 # Z-Shell Init
 #
 
-if [ -n "$0" ] && [ -f "$0" ]; then
-  DOTFILES="`dirname \"$0\"`"
-elif [ -d "$HOME/.dotfiles" ]; then
-  DOTFILES="$HOME/.dotfiles"
+# Fix PATH re-ordering done by macOS, by loading ~/.zshenv again.
+if [[ "$(uname)" == "Darwin" ]] && [ -x "/usr/libexec/path_helper" ]; then
+  source "$HOME/.zshenv"
 fi
 
-# ==============================================================================
-# Environment variables
-# ==============================================================================
-
-# Export path variables.
-DOTPFILES="$DOTFILES/private"
-DOTBIN="$DOTFILES/bin"
-DOTZSH="$DOTFILES/zsh"
-
-# Path helpers.
-source "$DOTZSH/path_helpers.zsh"
-
-# Ensure /usr/local/bin is before various system-paths
-path_prepend "/usr/local/bin"
-
-# Editors
-export EDITOR="emacsclient-wrapper"
-export GEM_EDITOR="mate"
-
-# Locale Setup
-export LC_ALL="en_US.UTF-8"
-export LANG="en_US.UTF-8"
-
-# ensure bin and sbin paths from /usr/local are in PATH
-path_add_after "/usr/local/sbin" "/usr/local/bin"
-
-# ensure bin and sbin paths from /usr are in PATH
-path_add_after "/usr/sbin" "/usr/bin"
-
-# Add user's bin directory to PATH
-path_prepend "$HOME/bin"
-
-# Add dotfiles' bin directory to PATH
-path_prepend "$DOTBIN"
-
-# Ensure TMPDIR is the same for local and remote ssh logins
-if [[ $TMPDIR == "/var/folders/"* ]] || [[ $TMPDIR == "" ]]; then
-  export TMPDIR="/tmp/user-$USER"
-  mkdir -p "$TMPDIR"
-fi
 
 # ==============================================================================
 # zplug
@@ -87,6 +46,16 @@ fi
 
 zplug load
 
+
+# ==============================================================================
+# Private Dotfiles
+# ==============================================================================
+
+if [ -f "$DOTPFILES/zshrc" ]; then
+  source "$DOTPFILES/zshrc"
+fi
+
+
 # ==============================================================================
 # Completion
 # ==============================================================================
@@ -97,29 +66,26 @@ autoload -Uz +X bashcompinit && bashcompinit
 
 fpath=("$DOTZSH/completion" "${fpath[@]}")
 
+
 # ==============================================================================
-# Load custom scripts
+# Tool specific setup
 # ==============================================================================
 
 # Aliases
 source "$DOTZSH/aliases.zsh"
 
 # OS specific
-source "$DOTZSH/osx.zsh"
-source "$DOTZSH/linux.zsh"
+if [[ "$(uname)" == "Darwin" ]]; then source "$DOTZSH/macos.zsh"; fi
+if [[ "$(uname)" == "Linux" ]]; then source "$DOTZSH/linux.zsh"; fi
 
 # Utils
 source "$DOTZSH/emacs.zsh"
 source "$DOTZSH/git.zsh"
-source "$DOTZSH/gnu-getopt.zsh"
-source "$DOTZSH/homebrew.zsh"
 source "$DOTZSH/less.zsh"
 source "$DOTZSH/tmux.zsh"
 
 # Development
-source "$DOTZSH/android-sdk.zsh"
 source "$DOTZSH/docker.zsh"
-source "$DOTZSH/flutter.zsh"
 source "$DOTZSH/golang.zsh"
 source "$DOTZSH/google-cloud.zsh"
 source "$DOTZSH/kubernetes.zsh"
@@ -132,6 +98,7 @@ if [ -f "$DOTPFILES/shellrc.sh" ]; then
   source "$DOTPFILES/shellrc.sh"
 fi
 
+
 # ==============================================================================
 # Basic Z-Shell settings
 # ==============================================================================
@@ -144,3 +111,12 @@ unsetopt share_history
 
 # Disable attempted correction of commands (is wrong 98% of the time).
 unsetopt correctall
+
+
+# ==============================================================================
+# Local Overrides
+# ==============================================================================
+
+if [ -f "$HOME/.zshrc.local" ]; then
+  source "$HOME/.zshrc.local"
+fi