diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..33ef847
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,11 @@
+# Ignore files generated by nested Zulu install
+tests/_support/.config/*
+tests/_support/.zulu/*
+tests/_support/zulu-install.zsh
+
+# Ignore output
+tests/_output/*
+!tests/_output/.gitkeep
+
+/zulu
+*.zwc
diff --git a/.guardian.yml b/.guardian.yml
new file mode 100644
index 0000000..f4c14e7
--- /dev/null
+++ b/.guardian.yml
@@ -0,0 +1,5 @@
+files: ./tests/commands/**/*
+run: zunit "%file%"
+---
+files: ./src/**/*.zsh
+run: ./build.zsh
diff --git a/build.zsh b/build.zsh
new file mode 100755
index 0000000..401191c
--- /dev/null
+++ b/build.zsh
@@ -0,0 +1,23 @@
+#!/usr/bin/env zsh
+
+# Clear the file to start with
+cat /dev/null > zulu
+
+# Start with the shebang
+echo "#!/usr/bin/env zsh\n" >> zulu
+
+# We need to do some fancy globbing
+setopt EXTENDED_GLOB
+
+# Print each of the source files into the target, removing any comments
+# and blank lines from the compiled executable
+cat src/**/(^zulu).zsh | grep -v -E '^(\s*#.*[^"]|\s*)$' >> zulu
+
+# Print the main command last
+cat src/zulu.zsh | grep -v -E '^(\s*#.*[^"]|\s*)$' >> zulu
+
+# Make sure the file is executable
+chmod u+x zulu
+
+# Let the user know we're finished
+echo "\033[0;32m✔\033[0;m zulu built successfully"
diff --git a/commands/alias b/src/commands/alias.zsh
similarity index 89%
rename from commands/alias
rename to src/commands/alias.zsh
index 3168a93..f1c99e9 100644
--- a/commands/alias
+++ b/src/commands/alias.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
@@ -16,7 +14,7 @@ function _zulu_alias_usage() {
 ###
 # Add an alias
 ###
-_zulu_alias_add() {
+function _zulu_alias_add() {
   local existing alias cmd
 
   alias="$1"
@@ -31,13 +29,13 @@ _zulu_alias_add() {
   echo "alias $alias='$cmd'" >> $aliasfile
 
   zulu alias load
-  return
+  echo "$(_zulu_color green '✔') Alias '$alias' added"
 }
 
 ###
 # Remove an alias
 ###
-_zulu_alias_rm() {
+function _zulu_alias_rm() {
   local existing alias
 
   alias="$1"
@@ -50,14 +48,15 @@ _zulu_alias_rm() {
 
   echo "$(cat $aliasfile | grep -v "alias $alias=")" >! $aliasfile
   unalias $alias
+
   zulu alias load
-  return
+  echo "$(_zulu_color green '✔') Alias '$alias' removed"
 }
 
 ###
 # Load aliases
 ###
-_zulu_alias_load() {
+function _zulu_alias_load() {
   source $aliasfile
 }
 
diff --git a/commands/bundle b/src/commands/bundle.zsh
similarity index 99%
rename from commands/bundle
rename to src/commands/bundle.zsh
index 261c350..58f3978 100644
--- a/commands/bundle
+++ b/src/commands/bundle.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
diff --git a/commands/cdpath b/src/commands/cdpath.zsh
similarity index 92%
rename from commands/cdpath
rename to src/commands/cdpath.zsh
index 54deacc..21f495d 100644
--- a/commands/cdpath
+++ b/src/commands/cdpath.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
@@ -108,13 +106,6 @@ function _zulu_cdpath_rm() {
 function _zulu_cdpath_store() {
   local separator out
 
-  # Check that we have all the parameters we need. This will only happen if
-  # _zulu_cdpath_store is executed internally.
-  if [[ "$items" = "" || "$pathfile" = "" ]]; then
-    echo 'Missing parameters. Was _zulu_cdpath_store called from within the add or remove functions?'
-    return 1
-  fi
-
   # Separate the array by newlines, and print the contents to the pathfile
   separator=$'\n'
   local IFS="$separator"; out="${items[*]/#/${separator}}"
diff --git a/src/commands/compile.zsh b/src/commands/compile.zsh
new file mode 100644
index 0000000..c31648c
--- /dev/null
+++ b/src/commands/compile.zsh
@@ -0,0 +1,90 @@
+#!/usr/bin/env zsh
+
+###
+# Output usage information and exit
+###
+function _zulu_compile_usage() {
+  echo '\033[0;32mUsage:\033[0;m'
+  echo '  zulu_compile [options]'
+}
+
+###
+# Resolve symbolic links to a file, a compare it's last-modified date
+# with the compiled version, recompiling if needed
+###
+function _zulu_compile_if_needed() {
+  local file="$1" follow_symlinks
+
+  zparseopts -D \
+    f=follow_symlinks -follow-symlinks=follow_symlinks
+
+  # We can't compile files that do not exist
+  [[ ! -e $file ]] && return
+
+  # Resolve symlinks if necessary
+  [[ -n $follow_symlinks && -L $file ]] && file=$(readlink $file)
+
+  # Check if the file is newer than it's compiled version,
+  # and recompile if necessary
+  if [[ -s ${file} && ( ! -s ${file}.zwc || ${file} -nt ${file}.zwc) ]]; then
+    zcompile ${file}
+  fi
+}
+
+###
+# The main zulu_compile process
+###
+(( $+functions[_zulu_compile] )) || function _zulu_compile() {
+  local base=${ZULU_DIR:-"${ZDOTDIR:-$HOME}/.zulu"}
+  local config=${ZULU_CONFIG_DIR:-"${ZDOTDIR:-$HOME}/.config/zulu"}
+  local help version
+
+  zparseopts -D \
+    h=help -help=help
+
+  if [[ -n $help ]]; then
+    _zulu_compile_usage
+    exit
+  fi
+
+  setopt EXTENDED_GLOB
+  # A list of glob paths pointing to files to be compiled
+  local -a compile_targets; compile_targets=(
+    # Zulu's core
+    ${base}/core/zulu
+
+    # Files linked by packages
+    ${base}/share/**/*^(*.zwc)(#q@)
+    ${base}/bin/**/*^(*.zwc)(#q@)
+
+    # Completion dump
+    ${ZDOTDIR:-${HOME}}/.zcomp^(*.zwc)(.)
+
+    # User env files
+    ${ZDOTDIR:-${HOME}}/.zshenv
+    ${ZDOTDIR:-${HOME}}/.zlogin
+    ${ZDOTDIR:-${HOME}}/.zprofile
+    ${ZDOTDIR:-${HOME}}/.zshrc
+    ${ZDOTDIR:-${HOME}}/.zlogout
+  )
+
+  # A second list of compile targets. These files have their symlinks resolved
+  # before they are sourced, so we need to follow the symlink before compiling,
+  # to ensure the compiled version is picked up
+  local -a linked_compile_targets; linked_compile_targets=(
+    # Initialisation scripts for packages
+    ${base}/init/**/*^(*.zwc)(#q@)
+  )
+
+  # Loop through each of the files marked for compilation, and compile
+  # them if necessary
+  for file in ${(@f)compile_targets}; do
+    _zulu_compile_if_needed $file
+  done
+
+  # Loop through each of the files marked for compilation, follow their
+  # symlinks, and compile them if necessary
+  for file in ${(@f)linked_compile_targets}; do
+    _zulu_compile_if_needed --follow-symlinks $file
+  done
+}
diff --git a/commands/fpath b/src/commands/fpath.zsh
similarity index 92%
rename from commands/fpath
rename to src/commands/fpath.zsh
index 78f3086..ef2f6f7 100644
--- a/commands/fpath
+++ b/src/commands/fpath.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
@@ -108,13 +106,6 @@ function _zulu_fpath_rm() {
 function _zulu_fpath_store() {
   local separator out
 
-  # Check that we have all the parameters we need. This will only happen if
-  # _zulu_fpath_store is executed internally.
-  if [[ "$items" = "" || "$pathfile" = "" ]]; then
-    echo 'Missing parameters. Was _zulu_fpath_store called from within the add or remove functions?'
-    return 1
-  fi
-
   # Separate the array by newlines, and print the contents to the pathfile
   separator=$'\n'
   local IFS="$separator"; out="${items[*]/#/${separator}}"
diff --git a/commands/func b/src/commands/func.zsh
similarity index 99%
rename from commands/func
rename to src/commands/func.zsh
index b5f21e9..a9a8e78 100644
--- a/commands/func
+++ b/src/commands/func.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/info b/src/commands/info.zsh
similarity index 98%
rename from commands/info
rename to src/commands/info.zsh
index 34269ca..3114a3c 100644
--- a/commands/info
+++ b/src/commands/info.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/init b/src/commands/init.zsh
similarity index 97%
rename from commands/init
rename to src/commands/init.zsh
index 2a579df..a9fef21 100644
--- a/commands/init
+++ b/src/commands/init.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 function _zulu_init_usage() {
   echo $(_zulu_color yellow "Usage:")
   echo "  zulu init [options]"
@@ -7,6 +5,7 @@ function _zulu_init_usage() {
   echo $(_zulu_color yellow "Options:")
   echo "  -c, --check-for-update   Check for updates on startup"
   echo "  -h, --help               Output this help text and exit"
+  echo "  -n, --no-compile         Skip compilation of scripts on startup"
 }
 
 function _zulu_init_setup_completion() {
@@ -557,21 +556,13 @@ function _zulu_check_for_update() {
   fi
 }
 
-###
-# Load the zulu commands
-###
-function _zulu_load_commands() {
-  for cmd in $(find "$base/core/commands"); do
-    source $cmd
-  done
-}
-
 ###
 # Source init scripts for installed packages
 ###
 function _zulu_load_packages() {
   # Source files in the init directory
-  for f in $(find "$base/init"); do
+  setopt EXTENDED_GLOB
+  for f in ${base}/init/**/*^(*.zwc)(#q@N); do
     if [[ -L $f ]]; then
       source $(readlink $f)
     else
@@ -586,33 +577,25 @@ function _zulu_load_packages() {
 function _zulu_init() {
   local base=${ZULU_DIR:-"${ZDOTDIR:-$HOME}/.zulu"}
   local config=${ZULU_CONFIG_DIR:-"${ZDOTDIR:-$HOME}/.config/zulu"}
-  local help check_for_update
-
-  # Ensure path arrays do not contain duplicates.
-  typeset -gU cdpath fpath mailpath path
+  local help check_for_update no_compile
 
   # Parse CLI options
   zparseopts -D \
     h=help -help=help \
-    c=check_for_update -check-for-update=check_for_update
+    c=check_for_update -check-for-update=check_for_update \
+    n=no_compile -no-compile=no_compile
 
   if [[ -n $help ]]; then
     _zulu_init_usage
     return
   fi
 
-  # Load zulu internal commands
-  _zulu_load_commands
-
   # Populate paths
   zulu path reset
   zulu fpath reset
   zulu cdpath reset
   zulu manpath reset
 
-  # Source helper functions
-  source "$base/core/helpers"
-
   # Set up the environment
   _zulu_init_setup_key_bindings
   _zulu_init_setup_completion
@@ -635,5 +618,11 @@ function _zulu_init() {
     prompt $theme
   fi
 
+  if [[ -z $no_compile ]]; then
+    {
+      zulu compile
+    } >/dev/null 2>&1 &!
+  fi
+
   [[ -n $check_for_update ]] && _zulu_check_for_update
 }
diff --git a/commands/install b/src/commands/install.zsh
similarity index 99%
rename from commands/install
rename to src/commands/install.zsh
index 117080d..024fbdd 100755
--- a/commands/install
+++ b/src/commands/install.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/link b/src/commands/link.zsh
similarity index 84%
rename from commands/link
rename to src/commands/link.zsh
index bb6ccc8..510c061 100644
--- a/commands/link
+++ b/src/commands/link.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
@@ -81,17 +79,20 @@ function _zulu_link() {
 
     # Loop through each of the values in the array, the key is a file within
     # the package, the value is the name of a symlink to create in the directory
-    for file link (${(@kv)files}) ln -s $root/${~file} $base/$dir/$link
-
-    # Make sure that commands to be included in bin are executable
-    if [[ "$dir" = "bin" ]]; then
-      for file link ("${(@kv)files}") chmod u+x "$root/$file"
-    fi
-
-    # Source init scripts
-    if [[ "$dir" = "init" ]]; then
-      for file link ("${(@kv)files}") source $(readlink "$base/init/$link")
-    fi
+    for file link in "${(@kv)files}"; do
+      # Create a symlink to the file, filtering out .zwc files
+      ln -s $root/${~file} $base/$dir/$link
+
+      # Make sure that commands to be included in bin are executable
+      if [[ "$dir" = "bin" ]]; then
+        chmod u+x "$root/$file"
+      fi
+
+      # Source init scripts
+      if [[ "$dir" = "init" ]]; then
+        source $(readlink "$base/init/$link")
+      fi
+    done
   done
 
   package_type=$(jsonval $json 'type')
diff --git a/commands/list b/src/commands/list.zsh
similarity index 99%
rename from commands/list
rename to src/commands/list.zsh
index 8a7033c..ba80889 100644
--- a/commands/list
+++ b/src/commands/list.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
diff --git a/commands/manpath b/src/commands/manpath.zsh
similarity index 99%
rename from commands/manpath
rename to src/commands/manpath.zsh
index da9d835..2c813b4 100644
--- a/commands/manpath
+++ b/src/commands/manpath.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/path b/src/commands/path.zsh
similarity index 92%
rename from commands/path
rename to src/commands/path.zsh
index 2ee5c0a..71c5d9c 100644
--- a/commands/path
+++ b/src/commands/path.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
@@ -108,13 +106,6 @@ function _zulu_path_rm() {
 function _zulu_path_store() {
   local separator out
 
-  # Check that we have all the parameters we need. This will only happen if
-  # _zulu_path_store is executed internally.
-  if [[ "$items" = "" || "$pathfile" = "" ]]; then
-    echo 'Missing parameters. Was _zulu_path_store called from within the add or remove functions?'
-    return 1
-  fi
-
   # Separate the array by newlines, and print the contents to the pathfile
   separator=$'\n'
   local IFS="$separator"; out="${items[*]/#/${separator}}"
diff --git a/commands/search b/src/commands/search.zsh
similarity index 97%
rename from commands/search
rename to src/commands/search.zsh
index 400984a..fa327bf 100644
--- a/commands/search
+++ b/src/commands/search.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/self-update b/src/commands/self-update.zsh
similarity index 99%
rename from commands/self-update
rename to src/commands/self-update.zsh
index 9f191d6..bf66c4f 100644
--- a/commands/self-update
+++ b/src/commands/self-update.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
@@ -20,6 +18,7 @@ function _zulu_self-update_core() {
 
   cd $core
   git fetch origin && git rebase origin
+  ./build.zsh
   cd $old
 }
 
diff --git a/commands/theme b/src/commands/theme.zsh
similarity index 97%
rename from commands/theme
rename to src/commands/theme.zsh
index 9f1075a..6db6998 100644
--- a/commands/theme
+++ b/src/commands/theme.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/uninstall b/src/commands/uninstall.zsh
similarity index 99%
rename from commands/uninstall
rename to src/commands/uninstall.zsh
index ba26806..069e57a 100644
--- a/commands/uninstall
+++ b/src/commands/uninstall.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/unlink b/src/commands/unlink.zsh
similarity index 98%
rename from commands/unlink
rename to src/commands/unlink.zsh
index 4743885..8e59526 100644
--- a/commands/unlink
+++ b/src/commands/unlink.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
diff --git a/commands/update b/src/commands/update.zsh
similarity index 99%
rename from commands/update
rename to src/commands/update.zsh
index bced634..fbb35fa 100644
--- a/commands/update
+++ b/src/commands/update.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
diff --git a/commands/upgrade b/src/commands/upgrade.zsh
similarity index 99%
rename from commands/upgrade
rename to src/commands/upgrade.zsh
index 4d6dddf..3476ebd 100644
--- a/commands/upgrade
+++ b/src/commands/upgrade.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/commands/var b/src/commands/var.zsh
similarity index 98%
rename from commands/var
rename to src/commands/var.zsh
index e120fd5..b06a5bd 100644
--- a/commands/var
+++ b/src/commands/var.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Output usage information
 ###
diff --git a/helpers b/src/helpers.zsh
similarity index 99%
rename from helpers
rename to src/helpers.zsh
index 8f18184..3201ad2 100644
--- a/helpers
+++ b/src/helpers.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Get the value for a key in a JSON object
 #
diff --git a/zulu b/src/zulu.zsh
similarity index 93%
rename from zulu
rename to src/zulu.zsh
index bbd0dcf..42bf362 100755
--- a/zulu
+++ b/src/zulu.zsh
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 ###
 # Print usage information
 ###
@@ -65,13 +63,6 @@ function _zulu_version() {
 
   cmd="$1"
 
-  # The init command needs to be loaded itself
-  if [[ $cmd = 'init' ]]; then
-    if (( ! $+functions[_zulu_init] )); then
-      source "$base/core/commands/init"
-    fi
-  fi
-
   if [[ -z $cmd ]]; then
     echo " _____         ___"
     echo "/__  /  __  __/  /_  __"