diff --git a/bash_it.sh b/bash_it.sh
index 03fd0bf5..78d19b87 100755
--- a/bash_it.sh
+++ b/bash_it.sh
@@ -1,145 +1,111 @@
 #!/usr/bin/env bash
+# shellcheck source-path=SCRIPTDIR/lib source-path=SCRIPTDIR/scripts
+# shellcheck disable=SC2034
+#
 # Initialize Bash It
 BASH_IT_LOG_PREFIX="core: main: "
-
-# Only set $BASH_IT if it's not already set
-if [ -z "${BASH_IT:-}" ]; then
-	# Setting $BASH to maintain backwards compatibility
-	export BASH_IT=$BASH
-	BASH="$(bash -c 'echo $BASH')"
-	export BASH
-	BASH_IT_OLD_BASH_SETUP=true
-fi
+: "${BASH_IT:=${BASH_SOURCE%/*}}"
+: "${BASH_IT_CUSTOM:=${BASH_IT}/custom}"
+: "${CUSTOM_THEME_DIR:="${BASH_IT_CUSTOM}/themes"}"
+: "${BASH_IT_BASHRC:=${BASH_SOURCE[${#BASH_SOURCE[@]} - 1]}}"
 
 # Load composure first, so we support function metadata
-# shellcheck disable=SC1090
-source "${BASH_IT}"/vendor/github.com/erichs/composure/composure.sh
-
-# Declare our end-of-main finishing hook
-declare -a _bash_it_library_finalize_hook
-
-# We need to load logging module early in order to be able to log
-# shellcheck source-path=SCRIPTDIR/lib
-source "${BASH_IT}/lib/log.bash"
-
-# We can only log it now
-[ -z "${BASH_IT_OLD_BASH_SETUP:-}" ] || _log_warning "BASH_IT variable not initialized, please upgrade your bash-it version and reinstall it!"
-
-# For backwards compatibility, look in old BASH_THEME location
-if [ -z "${BASH_IT_THEME:-}" ]; then
-	_log_warning "BASH_IT_THEME variable not initialized, please upgrade your bash-it version and reinstall it!"
-	export BASH_IT_THEME="${BASH_THEME:-}"
-	unset BASH_THEME
-fi
-
+# shellcheck source-path=SCRIPTDIR/vendor/github.com/erichs/composure
+source "${BASH_IT}/vendor/github.com/erichs/composure/composure.sh"
 # support 'plumbing' metadata
 cite _about _param _example _group _author _version
 cite about-alias about-plugin about-completion
 
+# Declare our end-of-main finishing hook, but don't use `declare`/`typeset`
+_bash_it_library_finalize_hook=()
+
+# We need to load logging module early in order to be able to log
+source "${BASH_IT}/lib/log.bash"
+
 # libraries, but skip appearance (themes) for now
 _log_debug "Loading libraries(except appearance)..."
-LIB="${BASH_IT}/lib/*.bash"
 APPEARANCE_LIB="${BASH_IT}/lib/appearance.bash"
-for _bash_it_config_file in $LIB; do
-	if [ "$_bash_it_config_file" != "$APPEARANCE_LIB" ]; then
-		filename=${_bash_it_config_file##*/}
-		filename=${filename%.bash}
-		BASH_IT_LOG_PREFIX="lib: ${filename}: "
-		_log_debug "Loading library file..."
-		# shellcheck disable=SC1090
-		source "$_bash_it_config_file"
-	fi
+for _bash_it_main_file_lib in "${BASH_IT}/lib"/*.bash; do
+	[[ "$_bash_it_main_file_lib" == "$APPEARANCE_LIB" ]] && continue
+	_bash-it-log-prefix-by-path "${_bash_it_main_file_lib}"
+	_log_debug "Loading library file..."
+	# shellcheck disable=SC1090
+	source "$_bash_it_main_file_lib"
+	BASH_IT_LOG_PREFIX="core: main: "
 done
 
-BASH_IT_LOG_PREFIX="core: main: "
-# Load the global "enabled" directory
-# "family" param is empty so that files get sources in glob order
-# shellcheck source=./scripts/reloader.bash
-source "${BASH_IT}/scripts/reloader.bash"
-
-# Load enabled aliases, completion, plugins
-for file_type in "aliases" "plugins" "completion"; do
-	# shellcheck source=./scripts/reloader.bash
-	source "${BASH_IT}/scripts/reloader.bash" "skip" "$file_type"
+# Load the global "enabled" directory, then enabled aliases, completion, plugins
+# "_bash_it_main_file_type" param is empty so that files get sourced in glob order
+for _bash_it_main_file_type in "" "aliases" "plugins" "completion"; do
+	BASH_IT_LOG_PREFIX="core: reloader: "
+	source "${BASH_IT}/scripts/reloader.bash" "${_bash_it_main_file_type:+skip}" "$_bash_it_main_file_type"
+	BASH_IT_LOG_PREFIX="core: main: "
 done
 
 # Load theme, if a theme was set
-if [[ -n "${BASH_IT_THEME}" ]]; then
-	_log_debug "Loading \"${BASH_IT_THEME}\" theme..."
+# shellcheck source-path=SCRIPTDIR/themes
+if [[ -n "${BASH_IT_THEME:-}" ]]; then
+	_log_debug "Loading theme '${BASH_IT_THEME}'."
 	BASH_IT_LOG_PREFIX="themes: githelpers: "
-	# shellcheck source=./themes/githelpers.theme.bash
 	source "${BASH_IT}/themes/githelpers.theme.bash"
 	BASH_IT_LOG_PREFIX="themes: p4helpers: "
-	# shellcheck source=./themes/p4helpers.theme.bash
 	source "${BASH_IT}/themes/p4helpers.theme.bash"
 	BASH_IT_LOG_PREFIX="themes: command_duration: "
-	# shellcheck source=./themes/command_duration.theme.bash
 	source "${BASH_IT}/themes/command_duration.theme.bash"
 	BASH_IT_LOG_PREFIX="themes: base: "
-	# shellcheck source=./themes/base.theme.bash
 	source "${BASH_IT}/themes/base.theme.bash"
 
 	BASH_IT_LOG_PREFIX="lib: appearance: "
 	# appearance (themes) now, after all dependencies
-	# shellcheck source=./lib/appearance.bash
+	# shellcheck source=SCRIPTDIR/lib/appearance.bash
 	source "$APPEARANCE_LIB"
+	BASH_IT_LOG_PREFIX="core: main: "
 fi
 
-BASH_IT_LOG_PREFIX="core: main: "
 _log_debug "Loading custom aliases, completion, plugins..."
-for file_type in "aliases" "completion" "plugins"; do
-	if [ -e "${BASH_IT}/${file_type}/custom.${file_type}.bash" ]; then
-		BASH_IT_LOG_PREFIX="${file_type}: custom: "
+for _bash_it_main_file_type in "aliases" "completion" "plugins"; do
+	_bash_it_main_file_custom="${BASH_IT}/${_bash_it_main_file_type}/custom.${_bash_it_main_file_type}.bash"
+	if [[ -s "${_bash_it_main_file_custom}" ]]; then
+		_bash-it-log-prefix-by-path "${_bash_it_main_file_custom}"
 		_log_debug "Loading component..."
 		# shellcheck disable=SC1090
-		source "${BASH_IT}/${file_type}/custom.${file_type}.bash"
+		source "${_bash_it_main_file_custom}"
 	fi
+	BASH_IT_LOG_PREFIX="core: main: "
 done
 
 # Custom
-BASH_IT_LOG_PREFIX="core: main: "
 _log_debug "Loading general custom files..."
-CUSTOM="${BASH_IT_CUSTOM:=${BASH_IT}/custom}/*.bash ${BASH_IT_CUSTOM:=${BASH_IT}/custom}/**/*.bash"
-for _bash_it_config_file in $CUSTOM; do
-	if [ -e "${_bash_it_config_file}" ]; then
-		filename=$(basename "${_bash_it_config_file}")
-		filename=${filename%*.bash}
-		# shellcheck disable=SC2034
-		BASH_IT_LOG_PREFIX="custom: $filename: "
+for _bash_it_main_file_custom in "${BASH_IT_CUSTOM}"/*.bash "${BASH_IT_CUSTOM}"/*/*.bash; do
+	if [[ -s "${_bash_it_main_file_custom}" ]]; then
+		_bash-it-log-prefix-by-path "${_bash_it_main_file_custom}"
 		_log_debug "Loading custom file..."
 		# shellcheck disable=SC1090
-		source "$_bash_it_config_file"
+		source "$_bash_it_main_file_custom"
 	fi
+	BASH_IT_LOG_PREFIX="core: main: "
 done
 
-unset _bash_it_config_file
 if [[ -n "${PROMPT:-}" ]]; then
-	export PS1="\[""$PROMPT""\]"
+	PS1="${PROMPT}"
 fi
 
 # Adding Support for other OSes
-PREVIEW="less"
-
-if [ -s /usr/bin/gloobus-preview ]; then
+if _command_exists gloobus-preview; then
 	PREVIEW="gloobus-preview"
-elif [ -s /Applications/Preview.app ]; then
-	# shellcheck disable=SC2034
+elif [[ -d /Applications/Preview.app ]]; then
 	PREVIEW="/Applications/Preview.app"
+else
+	PREVIEW="less"
 fi
 
 # BASH_IT_RELOAD_LEGACY is set.
-if ! _command_exists reload && [[ -n "${BASH_IT_RELOAD_LEGACY:-}" ]]; then
-	case $OSTYPE in
-		darwin*)
-			alias reload='source ~/.bash_profile'
-			;;
-		*)
-			alias reload='source ~/.bashrc'
-			;;
-	esac
+if [[ -n "${BASH_IT_RELOAD_LEGACY:-}" ]] && ! _command_exists reload; then
+	# shellcheck disable=SC2139
+	alias reload="builtin source '${BASH_IT_BASHRC?}'"
 fi
 
 for _bash_it_library_finalize_f in "${_bash_it_library_finalize_hook[@]:-}"; do
 	eval "${_bash_it_library_finalize_f?}" # Use `eval` to achieve the same behavior as `$PROMPT_COMMAND`.
 done
-unset "${!_bash_it_library_finalize_@}"
+unset "${!_bash_it_library_finalize_@}" "${!_bash_it_main_file_@}"
diff --git a/clean_files.txt b/clean_files.txt
index 8f9c173a..6ef4d247 100644
--- a/clean_files.txt
+++ b/clean_files.txt
@@ -83,8 +83,10 @@ completion/available/wpscan.completion.bash
 # libraries
 lib/colors.bash
 lib/helpers.bash
+lib/history.bash
 lib/log.bash
 lib/preexec.bash
+lib/preview.bash
 lib/search.bash
 lib/utilities.bash
 
diff --git a/completion/available/aliases.completion.bash b/completion/available/aliases.completion.bash
new file mode 100644
index 00000000..bdcaf917
--- /dev/null
+++ b/completion/available/aliases.completion.bash
@@ -0,0 +1,98 @@
+# shellcheck shell=bash
+about-plugin 'Automatic completion of aliases'
+# Load after all aliases and completions to understand what needs to be completed
+# BASH_IT_LOAD_PRIORITY: 800
+
+# References:
+# http://superuser.com/a/437508/119764
+# http://stackoverflow.com/a/1793178/1228454
+
+# Automatically add completion for all aliases to commands having completion functions
+function _bash-it-component-completion-callback-on-init-aliases() {
+	local namespace="alias_completion"
+	local tmp_file completion_loader alias_name line completions
+	local alias_arg_words new_completion compl_func compl_wrapper alias_defn
+
+	# create array of function completion triggers, keeping multi-word triggers together
+	IFS=$'\n' read -d '' -ra completions < <(complete -p)
+	((${#completions[@]} == 0)) && return 0
+
+	completions=("${completions[@]##complete -* * -}") # strip all but last option plus trigger(s)
+	completions=("${completions[@]#complete -}")       # strip anything missed
+	completions=("${completions[@]#? * }")             # strip last option and arg, leaving only trigger(s)
+
+	# create temporary file for wrapper functions and completions
+	tmp_file="$(mktemp -t "${namespace}-${RANDOM}XXXXXX")" || return 1
+
+	completion_loader="$(complete -p -D 2> /dev/null | sed -Ene 's/.* -F ([^ ]*).*/\1/p')"
+
+	# read in "<alias> '<aliased command>' '<command args>'" lines from defined aliases
+	# some aliases do have backslashes that needs to be interpreted
+	# shellcheck disable=SC2162
+	while read line; do
+		line="${line#alias }"
+		alias_name="${line%%=*}"
+		alias_defn="${line#*=}"                 # alias definition
+		alias_cmd="${alias_defn%%[[:space:]]*}" # first word of alias
+		alias_cmd="${alias_cmd:1}"              # lose opening quotation mark
+		alias_args="${alias_defn#*[[:space:]]}" # everything after first word
+		alias_args="${alias_args%\'}"           # lose ending quotation mark
+
+		# skip aliases to pipes, boolean control structures and other command lists
+		[[ "${alias_args}" =~ [\|\&\;\)\(\n] ]] && continue
+		# avoid expanding wildcards
+		read -a alias_arg_words <<< "$alias_args"
+
+		# skip alias if there is no completion function triggered by the aliased command
+		if ! _bash-it-array-contains-element "$alias_cmd" "${completions[@]}"; then
+			if [[ -n "$completion_loader" ]]; then
+				# force loading of completions for the aliased command
+				"${completion_loader:?}" "${alias_cmd}"
+				# 124 means completion loader was successful
+				[[ $? -eq 124 ]] || continue
+				completions+=("$alias_cmd")
+			else
+				continue
+			fi
+		fi
+		new_completion="$(complete -p "$alias_cmd" 2> /dev/null)"
+
+		# create a wrapper inserting the alias arguments if any
+		if [[ -n $alias_args ]]; then
+			compl_func="${new_completion/#* -F /}"
+			compl_func="${compl_func%% *}"
+			# avoid recursive call loops by ignoring our own functions
+			if [[ "${compl_func#_"$namespace"::}" == "$compl_func" ]]; then
+				compl_wrapper="_${namespace}::${alias_name}"
+				echo "function $compl_wrapper {
+                        local compl_word=\$2
+                        local prec_word=\$3
+                        # check if prec_word is the alias itself. if so, replace it
+                        # with the last word in the unaliased form, i.e.,
+                        # alias_cmd + ' ' + alias_args.
+                        if [[ \$COMP_LINE == \"\$prec_word \$compl_word\" ]]; then
+                            prec_word='$alias_cmd $alias_args'
+                            prec_word=\${prec_word#* }
+                        fi
+                        (( COMP_CWORD += ${#alias_arg_words[@]} ))
+                        COMP_WORDS=($alias_cmd $alias_args \${COMP_WORDS[@]:1})
+                        (( COMP_POINT -= \${#COMP_LINE} ))
+                        COMP_LINE=\${COMP_LINE/$alias_name/$alias_cmd $alias_args}
+                        (( COMP_POINT += \${#COMP_LINE} ))
+                        $compl_func \"$alias_cmd\" \"\$compl_word\" \"\$prec_word\"
+                    }" >> "$tmp_file"
+				new_completion="${new_completion/ -F $compl_func / -F $compl_wrapper }"
+			fi
+		fi
+
+		# replace completion trigger by alias
+		if [[ -n $new_completion ]]; then
+			new_completion="${new_completion% *} $alias_name"
+			echo "$new_completion" >> "$tmp_file"
+		fi
+	done < <(alias -p)
+	# shellcheck source=/dev/null
+	source "$tmp_file" && command rm -f "$tmp_file"
+}
+
+_bash-it-component-completion-callback-on-init-aliases
diff --git a/completion/available/bash-it.completion.bash b/completion/available/bash-it.completion.bash
index 1f83d5c8..2259e37b 100644
--- a/completion/available/bash-it.completion.bash
+++ b/completion/available/bash-it.completion.bash
@@ -13,7 +13,7 @@ function _bash-it() {
 	prev="${COMP_WORDS[COMP_CWORD - 1]}"
 	verb="${COMP_WORDS[1]}"
 	file_type="${COMP_WORDS[2]:-}"
-	candidates=('disable' 'enable' 'help' 'migrate' 'reload' 'restart' 'profile' 'doctor' 'search' 'show' 'update' 'version')
+	candidates=('disable' 'enable' 'help' 'migrate' 'reload' 'restart' 'preview' 'profile' 'doctor' 'search' 'show' 'update' 'version')
 	case "${verb}" in
 		show)
 			candidates=('aliases' 'completions' 'plugins')
@@ -59,6 +59,10 @@ function _bash-it() {
 			_compreply_candidates
 			;;
 		migrate | reload | restart | search | version) ;;
+		preview)
+			_bash-it-preview # completes itself
+			return 0
+			;;
 		enable | disable)
 			if [[ "${verb}" == "enable" ]]; then
 				suffix="disabled"
diff --git a/completion/available/system.completion.bash b/completion/available/system.completion.bash
index af7ea70d..bb1d14eb 100644
--- a/completion/available/system.completion.bash
+++ b/completion/available/system.completion.bash
@@ -14,31 +14,24 @@ else
 	__bash_it_restore_nounset=false
 fi
 
+# shellcheck disable=SC1090 disable=SC1091
 if [[ -r "${BASH_COMPLETION:-}" ]]; then
-	# shellcheck disable=SC1090
 	source "${BASH_COMPLETION}"
-
 elif [[ -r /etc/bash_completion ]]; then
-	# shellcheck disable=SC1091
 	source /etc/bash_completion
-
 # Some distribution makes use of a profile.d script to import completion.
 elif [[ -r /etc/profile.d/bash_completion.sh ]]; then
-	# shellcheck disable=SC1091
 	source /etc/profile.d/bash_completion.sh
-
 elif _bash_it_homebrew_check; then
-	: "${BASH_COMPLETION_COMPAT_DIR:=$BASH_IT_HOMEBREW_PREFIX/etc/bash_completion.d}"
-
+	: "${BASH_COMPLETION_COMPAT_DIR:=${BASH_IT_HOMEBREW_PREFIX}/etc/bash_completion.d}"
 	case "${BASH_VERSION}" in
 		1* | 2* | 3.0* | 3.1*)
 			_log_warning "Cannot load completion due to version of shell. Are you using Bash 3.2+?"
 			;;
 		3.2* | 4.0* | 4.1*)
 			# Import version 1.x of bash-completion, if installed.
-			BASH_COMPLETION="$BASH_IT_HOMEBREW_PREFIX/opt/bash-completion@1/etc/bash_completion"
+			BASH_COMPLETION="${BASH_IT_HOMEBREW_PREFIX}/opt/bash-completion@1/etc/bash_completion"
 			if [[ -r "$BASH_COMPLETION" ]]; then
-				# shellcheck disable=SC1090
 				source "$BASH_COMPLETION"
 			else
 				unset BASH_COMPLETION
@@ -46,9 +39,8 @@ elif _bash_it_homebrew_check; then
 			;;
 		4.2* | 5* | *)
 			# homebrew/versions/bash-completion2 (required for projects.completion.bash) is installed to this path
-			if [[ -r "${BASH_IT_HOMEBREW_PREFIX}/etc/profile.d/bash_completion.sh" ]]; then
-				# shellcheck disable=SC1091
-				source "${BASH_IT_HOMEBREW_PREFIX}/etc/profile.d/bash_completion.sh"
+			if [[ -r "${BASH_IT_HOMEBREW_PREFIX}/opt/bash-completion@2/etc/profile.d/bash_completion.sh" ]]; then
+				source "${BASH_IT_HOMEBREW_PREFIX}/opt/bash-completion@2/etc/profile.d/bash_completion.sh"
 			fi
 			;;
 	esac
diff --git a/docs/themes.rst b/docs/themes.rst
index 5b796389..8cfbeb23 100644
--- a/docs/themes.rst
+++ b/docs/themes.rst
@@ -22,7 +22,7 @@ Examples:
    # Disable theming
    export BASH_IT_THEME=""
 
-You can easily preview the themes in your own shell using ``BASH_PREVIEW=true bash-it reload``.
+You can easily preview the themes in your own shell using ``bash-it preview``.
 
 If you've created your own custom prompts, we'd love it if you shared them with everyone else! Just submit a Pull Request.
 You can see theme screenshots on `wiki/Themes <https://github.com/Bash-it/bash-it/wiki/Themes>`_.
diff --git a/lib/helpers.bash b/lib/helpers.bash
index 66cdec74..4728541a 100644
--- a/lib/helpers.bash
+++ b/lib/helpers.bash
@@ -98,7 +98,7 @@ alias reload_plugins="$(_make_reload_alias plugin plugins)"
 
 function bash-it() {
 	about 'Bash-it help and maintenance'
-	param '1: verb [one of: help | show | enable | disable | migrate | update | search | version | reload | restart | doctor ] '
+	param '1: verb [one of: help | show | enable | disable | migrate | update | search | preview | version | reload | restart | doctor ] '
 	param '2: component type [one of: alias(es) | completion(s) | plugin(s) ] or search term(s)'
 	param '3: specific component [optional]'
 	example '$ bash-it show plugins'
@@ -108,6 +108,8 @@ function bash-it() {
 	example '$ bash-it migrate'
 	example '$ bash-it update'
 	example '$ bash-it search [-|@]term1 [-|@]term2 ... [ -e/--enable ] [ -d/--disable ] [ -r/--refresh ] [ -c/--no-color ]'
+	example '$ bash-it preview'
+	example '$ bash-it preview essential'
 	example '$ bash-it version'
 	example '$ bash-it reload'
 	example '$ bash-it restart'
@@ -142,6 +144,10 @@ function bash-it() {
 			_bash-it-search "$component" "$@"
 			return
 			;;
+		preview)
+			_bash-it-preview "$component" "$@"
+			return
+			;;
 		update)
 			func="_bash-it-update-$component"
 			;;
diff --git a/lib/history.bash b/lib/history.bash
new file mode 100644
index 00000000..7bdbbd5e
--- /dev/null
+++ b/lib/history.bash
@@ -0,0 +1,49 @@
+# shellcheck shell=bash
+#
+# Functions for working with Bash's command history.
+
+function _bash-it-history-init() {
+	safe_append_preexec '_bash-it-history-auto-save'
+	safe_append_prompt_command '_bash-it-history-auto-load'
+}
+
+function _bash-it-history-auto-save() {
+	case $HISTCONTROL in
+		*'noauto'* | *'autoload'*)
+			: # Do nothing, as configured.
+			;;
+		*'auto'*)
+			# Append new history from this session to the $HISTFILE
+			history -a
+			;;
+		*)
+			# Append *only* if shell option `histappend` has been enabled.
+			shopt -q histappend && history -a && return
+			;;
+	esac
+}
+
+function _bash-it-history-auto-load() {
+	case $HISTCONTROL in
+		*'noauto'*)
+			: # Do nothing, as configured.
+			;;
+		*'autosave'*)
+			# Append new history from this session to the $HISTFILE
+			history -a
+			;;
+		*'autoloadnew'*)
+			# Read new entries from $HISTFILE
+			history -n
+			;;
+		*'auto'*)
+			# Blank in-memory history, then read entire $HISTFILE fresh from disk.
+			history -a && history -c && history -r
+			;;
+		*)
+			: # Do nothing, default.
+			;;
+	esac
+}
+
+_bash_it_library_finalize_hook+=('_bash-it-history-init')
diff --git a/lib/preview.bash b/lib/preview.bash
index 418839cd..96fafae7 100644
--- a/lib/preview.bash
+++ b/lib/preview.bash
@@ -1,19 +1,34 @@
-if [[ "${BASH_PREVIEW:-}" ]];
-then
-  unset BASH_PREVIEW #Prevent infinite looping
-  echo "
+# shellcheck shell=bash
+#
+# Displays the prompt from each _Bash It_ theme.
 
-  Previewing Bash-it Themes
+function _bash-it-preview() {
+	local BASH_IT_THEME BASH_IT_LOG_LEVEL
+	local themes IFS=$'\n' cur
 
-  "
+	if [[ $# -gt '0' ]]; then
+		themes=("$@")
+	else
+		themes=("${BASH_IT?}/themes"/*/*.theme.bash)
+		themes=("${themes[@]##*/}")
+		themes=("${themes[@]%.theme.bash}")
+	fi
 
-  THEMES="$BASH_IT/themes/*/*.theme.bash"
-  for theme in $THEMES
-  do
-    BASH_IT_THEME=${theme%.theme.bash}
-    BASH_IT_THEME=${BASH_IT_THEME##*/}
-    echo "
-    $BASH_IT_THEME"
-    echo "" | bash --init-file "${BASH_IT}/bash_it.sh" -i
-  done
+	if [[ ${COMP_CWORD:-} -gt '0' ]]; then
+		cur="${COMP_WORDS[COMP_CWORD]}"
+		read -d '' -ra COMPREPLY < <(compgen -W "all${IFS}${themes[*]}" -- "${cur}")
+		return
+	fi
+	printf '\n\n\t%s\n\n' "Previewing Bash-it Themes"
+
+	# shellcheck disable=SC2034
+	for BASH_IT_THEME in "${themes[@]}"; do
+		BASH_IT_LOG_LEVEL=0
+		bash --init-file "${BASH_IT_BASHRC:-${BASH_IT?}/bash_it.sh}" -i <<< '_bash-it-flash-term "${#BASH_IT_THEME}" "${BASH_IT_THEME}"'
+	done
+}
+
+if [[ -n "${BASH_PREVIEW:-}" ]]; then
+	_bash-it-preview "${BASH_PREVIEW}" "$@"
+	unset BASH_PREVIEW #Prevent infinite looping
 fi
diff --git a/plugins/available/alias-completion.plugin.bash b/plugins/available/alias-completion.plugin.bash
index eb368d93..84c59a1e 100644
--- a/plugins/available/alias-completion.plugin.bash
+++ b/plugins/available/alias-completion.plugin.bash
@@ -1,105 +1,5 @@
 # shellcheck shell=bash
-# Load after the other completions to understand what needs to be completed
-# BASH_IT_LOAD_PRIORITY: 365
+# stub for renamed file
 
-cite about-plugin
-about-plugin 'Automatic completion of aliases'
-
-# References:
-# http://superuser.com/a/437508/119764
-# http://stackoverflow.com/a/1793178/1228454
-
-# This needs to be a plugin so it gets executed after the completions and the aliases have been defined.
-# Bash-it loads its components in the order
-# 1) Aliases
-# 2) Completions
-# 3) Plugins
-# 4) Custom scripts
-
-# Automatically add completion for all aliases to commands having completion functions
-function alias_completion {
-	local namespace="alias_completion"
-	local tmp_file completion_loader alias_name alias_tokens line completions
-	local alias_arg_words new_completion compl_func compl_wrapper
-
-	# parse function based completion definitions, where capture group 2 => function and 3 => trigger
-	local compl_regex='complete( +[^ ]+)* -F ([^ ]+) ("[^"]+"|[^ ]+)'
-	# parse alias definitions, where capture group 1 => trigger, 2 => command, 3 => command arguments
-	local alias_regex="alias( -- | )([^=]+)='(\"[^\"]+\"|[^ ]+)(( +[^ ]+)*)'"
-
-	# create array of function completion triggers, keeping multi-word triggers together
-	eval "completions=($(complete -p | sed -Ene "/$compl_regex/s//'\3'/p"))"
-	((${#completions[@]} == 0)) && return 0
-
-	# create temporary file for wrapper functions and completions
-	tmp_file="$(mktemp -t "${namespace}-${RANDOM}XXXXXX")" || return 1
-
-	completion_loader="$(complete -p -D 2> /dev/null | sed -Ene 's/.* -F ([^ ]*).*/\1/p')"
-
-	# read in "<alias> '<aliased command>' '<command args>'" lines from defined aliases
-	# some aliases do have backslashes that needs to be interpreted
-	# shellcheck disable=SC2162
-	while read line; do
-		eval "alias_tokens=($line)" 2> /dev/null || continue # some alias arg patterns cause an eval parse error
-		# shellcheck disable=SC2154 # see `eval` above
-		alias_name="${alias_tokens[0]}" alias_cmd="${alias_tokens[1]}" alias_args="${alias_tokens[2]# }"
-
-		# skip aliases to pipes, boolean control structures and other command lists
-		# (leveraging that eval errs out if $alias_args contains unquoted shell metacharacters)
-		eval "alias_arg_words=($alias_args)" 2> /dev/null || continue
-		# avoid expanding wildcards
-		read -a alias_arg_words <<< "$alias_args"
-
-		# skip alias if there is no completion function triggered by the aliased command
-		if ! _bash-it-array-contains-element "$alias_cmd" "${completions[@]}"; then
-			if [[ -n "$completion_loader" ]]; then
-				# force loading of completions for the aliased command
-				eval "$completion_loader $alias_cmd"
-				# 124 means completion loader was successful
-				[[ $? -eq 124 ]] || continue
-				completions+=("$alias_cmd")
-			else
-				continue
-			fi
-		fi
-		new_completion="$(complete -p "$alias_cmd" 2> /dev/null)"
-
-		# create a wrapper inserting the alias arguments if any
-		if [[ -n $alias_args ]]; then
-			compl_func="${new_completion/#* -F /}"
-			compl_func="${compl_func%% *}"
-			# avoid recursive call loops by ignoring our own functions
-			if [[ "${compl_func#_"$namespace"::}" == "$compl_func" ]]; then
-				compl_wrapper="_${namespace}::${alias_name}"
-				echo "function $compl_wrapper {
-                        local compl_word=\$2
-                        local prec_word=\$3
-                        # check if prec_word is the alias itself. if so, replace it
-                        # with the last word in the unaliased form, i.e.,
-                        # alias_cmd + ' ' + alias_args.
-                        if [[ \$COMP_LINE == \"\$prec_word \$compl_word\" ]]; then
-                            prec_word='$alias_cmd $alias_args'
-                            prec_word=\${prec_word#* }
-                        fi
-                        (( COMP_CWORD += ${#alias_arg_words[@]} ))
-                        COMP_WORDS=($alias_cmd $alias_args \${COMP_WORDS[@]:1})
-                        (( COMP_POINT -= \${#COMP_LINE} ))
-                        COMP_LINE=\${COMP_LINE/$alias_name/$alias_cmd $alias_args}
-                        (( COMP_POINT += \${#COMP_LINE} ))
-                        $compl_func \"$alias_cmd\" \"\$compl_word\" \"\$prec_word\"
-                    }" >> "$tmp_file"
-				new_completion="${new_completion/ -F $compl_func / -F $compl_wrapper }"
-			fi
-		fi
-
-		# replace completion trigger by alias
-		if [[ -n $new_completion ]]; then
-			new_completion="${new_completion% *} $alias_name"
-			echo "$new_completion" >> "$tmp_file"
-		fi
-	done < <(alias -p | sed -Ene "s/$alias_regex/\2 '\3' '\4'/p")
-	# shellcheck source=/dev/null
-	source "$tmp_file" && command rm -f "$tmp_file"
-}
-
-alias_completion
+_enable-completion aliases && _disable-plugin alias-completion
+source "${BASH_IT?}/completion/aliases.completion.bash"
diff --git a/plugins/available/battery.plugin.bash b/plugins/available/battery.plugin.bash
index dc18167c..1f758e0c 100644
--- a/plugins/available/battery.plugin.bash
+++ b/plugins/available/battery.plugin.bash
@@ -2,8 +2,10 @@
 about-plugin 'display info about your battery charge level'
 
 function ac_adapter_connected() {
+	local batteries
 	if _command_exists upower; then
-		upower -i "$(upower -e | grep -i BAT)" | grep 'state' | grep -q 'charging\|fully-charged'
+		batteries="$(upower -e | grep --max-count=1 -i BAT)"
+		upower -i "${batteries}" | grep 'state' | grep -q 'charging\|fully-charged'
 	elif _command_exists acpi; then
 		acpi -a | grep -q "on-line"
 	elif _command_exists pmset; then
@@ -16,8 +18,10 @@ function ac_adapter_connected() {
 }
 
 function ac_adapter_disconnected() {
+	local batteries
 	if _command_exists upower; then
-		upower -i "$(upower -e | grep -i BAT)" | grep 'state' | grep -q 'discharging'
+		batteries="$(upower -e | grep --max-count=1 -i BAT)"
+		upower -i "${batteries}" | grep 'state' | grep -q 'discharging'
 	elif _command_exists acpi; then
 		acpi -a | grep -q "off-line"
 	elif _command_exists pmset; then
@@ -33,16 +37,17 @@ function battery_percentage() {
 	about 'displays battery charge as a percentage of full (100%)'
 	group 'battery'
 
-	local command_output="no"
+	local command_output batteries
 
 	if _command_exists upower; then
-		command_output=$(upower --show-info "$(upower --enumerate | grep -i BAT)" | grep percentage | grep -o "[0-9]\+" | head -1)
+		batteries="$(upower --enumerate | grep --max-count=1 -i BAT)"
+		command_output="$(upower --show-info "${batteries:-}" | grep percentage | grep -o '[0-9]\+' | head -1)"
 	elif _command_exists acpi; then
 		command_output=$(acpi -b | awk -F, '/,/{gsub(/ /, "", $0); gsub(/%/,"", $0); print $2}')
 	elif _command_exists pmset; then
-		command_output=$(pmset -g ps | sed -n 's/.*[[:blank:]]+*\(.*%\).*/\1/p' | grep -o "[0-9]\+" | head -1)
+		command_output=$(pmset -g ps | sed -n 's/.*[[:blank:]]+*\(.*%\).*/\1/p' | grep -o '[0-9]\+' | head -1)
 	elif _command_exists ioreg; then
-		command_output=$(ioreg -n AppleSmartBattery -r | awk '$1~/Capacity/{c[$1]=$3} END{OFMT="%05.2f"; max=c["\"MaxCapacity\""]; print (max>0? 100*c["\"CurrentCapacity\""]/max: "?")}' | grep -o "[0-9]\+" | head -1)
+		command_output=$(ioreg -n AppleSmartBattery -r | awk '$1~/Capacity/{c[$1]=$3} END{OFMT="%05.2f"; max=c["\"MaxCapacity\""]; print (max>0? 100*c["\"CurrentCapacity\""]/max: "?")}' | grep -o '[0-9]\+' | head -1)
 	elif _command_exists WMIC; then
 		command_output=$(WMIC PATH Win32_Battery Get EstimatedChargeRemaining /Format:List | grep -o '[0-9]\+' | head -1)
 	else
diff --git a/plugins/available/history-eternal.plugin.bash b/plugins/available/history-eternal.plugin.bash
index a18283d3..829868df 100644
--- a/plugins/available/history-eternal.plugin.bash
+++ b/plugins/available/history-eternal.plugin.bash
@@ -1,20 +1,22 @@
 # shellcheck shell=bash
 about-plugin 'eternal bash history'
 
-# Load after the history plugin
-# BASH_IT_LOAD_PRIORITY: 375
+if [[ ${BASH_VERSINFO[0]} -lt 4 ]] || [[ ${BASH_VERSINFO[0]} -eq 4 && ${BASH_VERSINFO[1]} -lt 3 ]]; then
+	_log_warning "Bash version 4.3 introduced the 'unlimited' history size capability."
+	return 1
+fi
 
 # Modify history sizes before changing location to avoid unintentionally
 # truncating the history file early.
 
 # "Numeric values less than zero result in every command being saved on the history list (there is no limit)"
-export HISTSIZE=-1
+readonly HISTSIZE=-1 2> /dev/null || true
 
 # "Non-numeric values and numeric values less than zero inhibit truncation"
-export HISTFILESIZE='unlimited'
+readonly HISTFILESIZE='unlimited' 2> /dev/null || true
 
 # Use a custom history file location so history is not truncated
 # if the environment ever loses this "eternal" configuration.
 HISTDIR="${XDG_STATE_HOME:-${HOME?}/.local/state}/bash"
 [[ -d ${HISTDIR?} ]] || mkdir -p "${HISTDIR?}"
-export HISTFILE="${HISTDIR?}/history"
+readonly HISTFILE="${HISTDIR?}/history" 2> /dev/null || true
diff --git a/plugins/available/history-search.plugin.bash b/plugins/available/history-search.plugin.bash
index 341ce2af..96941993 100644
--- a/plugins/available/history-search.plugin.bash
+++ b/plugins/available/history-search.plugin.bash
@@ -1,9 +1,6 @@
 # shellcheck shell=bash
 about-plugin 'search history using the prefix already entered'
 
-# Load after the history plugin
-# BASH_IT_LOAD_PRIORITY: 375
-
 # enter a few characters and press UpArrow/DownArrow
 # to search backwards/forwards through the history
 if [[ ${SHELLOPTS} =~ (vi|emacs) ]]; then
diff --git a/plugins/available/history-substring-search.plugin.bash b/plugins/available/history-substring-search.plugin.bash
index 586ceb50..dde32720 100644
--- a/plugins/available/history-substring-search.plugin.bash
+++ b/plugins/available/history-substring-search.plugin.bash
@@ -1,9 +1,6 @@
 # shellcheck shell=bash
 about-plugin 'search history using the substring already entered'
 
-# Load after the history plugin
-# BASH_IT_LOAD_PRIORITY: 375
-
 # enter a few characters and press UpArrow/DownArrow
 # to search backwards/forwards through the history
 if [[ ${SHELLOPTS} =~ (vi|emacs) ]]; then
diff --git a/plugins/available/history.plugin.bash b/plugins/available/history.plugin.bash
index be253e4a..d9e930c3 100644
--- a/plugins/available/history.plugin.bash
+++ b/plugins/available/history.plugin.bash
@@ -5,14 +5,13 @@ about-plugin 'improve history handling with sane defaults'
 # variable when the shell exits, rather than overwriting the file.
 shopt -s histappend
 
-# erase duplicates; alternative option: export HISTCONTROL=ignoredups
-export HISTCONTROL=${HISTCONTROL:-ignorespace:erasedups}
+# 'ignorespace': don't save command lines which begin with a space to history
+# 'erasedups' (alternative 'ignoredups'): don't save duplicates to history
+# 'autoshare': automatically share history between multiple running shells
+: "${HISTCONTROL:=ignorespace:erasedups:autoshare}"
 
 # resize history to 100x the default (500)
-export HISTSIZE=${HISTSIZE:-50000}
-
-# Flush history to disk after each command.
-export PROMPT_COMMAND="history -a;${PROMPT_COMMAND}"
+: "${HISTSIZE:=50000}"
 
 function top-history() {
 	about 'print the name and count of the most commonly run tools'
diff --git a/profiles/default.bash_it b/profiles/default.bash_it
index 5e4f4631..9a55f6c7 100644
--- a/profiles/default.bash_it
+++ b/profiles/default.bash_it
@@ -1,10 +1,10 @@
 # This is the default profile of Bash-it
 
 # plugins
-plugins alias-completion
 plugins base
 
 # completion
+completion aliases
 completion bash-it
 completion system
 
diff --git a/test/plugins/alias-completion.plugin.bats b/test/completion/aliases.completion.bats
similarity index 80%
rename from test/plugins/alias-completion.plugin.bats
rename to test/completion/aliases.completion.bats
index 20d13cf2..813a7bbd 100644
--- a/test/plugins/alias-completion.plugin.bats
+++ b/test/completion/aliases.completion.bats
@@ -3,25 +3,26 @@
 load ../test_helper
 load ../test_helper_libs
 
+# Load something, anything...
 load ../../completion/available/capistrano.completion
 
 @test "alias-completion: See that aliases with double quotes and brackets do not break the plugin" {
   alias gtest="git log --graph --pretty=format:'%C(bold)%h%Creset%C(magenta)%d%Creset %s %C(yellow)<%an> %C(cyan)(%cr)%Creset' --abbrev-commit --date=relative"
-  load ../../plugins/available/alias-completion.plugin
+  run load ../../completion/available/aliases.completion
 
   assert_success
 }
 
 @test "alias-completion: See that aliases with single quotes and brackets do not break the plugin" {
   alias gtest='git log --graph --pretty=format:"%C(bold)%h%Creset%C(magenta)%d%Creset %s %C(yellow)<%an> %C(cyan)(%cr)%Creset" --abbrev-commit --date=relative'
-  load ../../plugins/available/alias-completion.plugin
+  run load ../../completion/available/aliases.completion
 
   assert_success
 }
 
 @test "alias-completion: See that having aliased rm command does not output unnecessary output" {
   alias rm='rm -v'
-  load ../../plugins/available/alias-completion.plugin
+  run load ../../completion/available/aliases.completion
 
   refute_output
 }
diff --git a/test/completion/bash-it.completion.bats b/test/completion/bash-it.completion.bats
index f2336185..087a926d 100755
--- a/test/completion/bash-it.completion.bats
+++ b/test/completion/bash-it.completion.bats
@@ -81,32 +81,32 @@ function __check_completion () {
 
 @test "completion bash-it: show options" {
   run __check_completion 'bash-it '
-  assert_line -n 0 "disable enable help migrate reload restart profile doctor search show update version"
+  assert_line -n 0 "disable enable help migrate reload restart preview profile doctor search show update version"
 }
 
 @test "completion bash-it: bash-ti - show options" {
   run __check_completion 'bash-ti '
-  assert_line -n 0 "disable enable help migrate reload restart profile doctor search show update version"
+  assert_line -n 0 "disable enable help migrate reload restart preview profile doctor search show update version"
 }
 
 @test "completion bash-it: shit - show options" {
   run __check_completion 'shit '
-  assert_line -n 0 "disable enable help migrate reload restart profile doctor search show update version"
+  assert_line -n 0 "disable enable help migrate reload restart preview profile doctor search show update version"
 }
 
 @test "completion bash-it: bashit - show options" {
   run __check_completion 'bashit '
-  assert_line -n 0 "disable enable help migrate reload restart profile doctor search show update version"
+  assert_line -n 0 "disable enable help migrate reload restart preview profile doctor search show update version"
 }
 
 @test "completion bash-it: batshit - show options" {
   run __check_completion 'batshit '
-  assert_line -n 0 "disable enable help migrate reload restart profile doctor search show update version"
+  assert_line -n 0 "disable enable help migrate reload restart preview profile doctor search show update version"
 }
 
 @test "completion bash-it: bash_it - show options" {
   run __check_completion 'bash_it '
-  assert_line -n 0 "disable enable help migrate reload restart profile doctor search show update version"
+  assert_line -n 0 "disable enable help migrate reload restart preview profile doctor search show update version"
 }
 
 @test "completion bash-it: profile - show options" {
diff --git a/test/fixtures/bash_it/profiles/test-bad-component.bash_it b/test/fixtures/bash_it/profiles/test-bad-component.bash_it
index 8640265c..068c4b63 100644
--- a/test/fixtures/bash_it/profiles/test-bad-component.bash_it
+++ b/test/fixtures/bash_it/profiles/test-bad-component.bash_it
@@ -1,8 +1,8 @@
 # plugins
-plugins alias-completion
 plugins base
 
 # completion
+completion aliases
 completion bash-it
 completion system
 
diff --git a/test/fixtures/bash_it/profiles/test-bad-type.bash_it b/test/fixtures/bash_it/profiles/test-bad-type.bash_it
index ed2d2373..102c52ea 100644
--- a/test/fixtures/bash_it/profiles/test-bad-type.bash_it
+++ b/test/fixtures/bash_it/profiles/test-bad-type.bash_it
@@ -1,10 +1,10 @@
 # plugins
-plugins alias-completion
 plugins base
 # Bad type
-pluugins alias-completion
+compleetion aliases
 
 # completion
+completion aliases
 completion bash-it
 completion system
 
diff --git a/test/install/install.bats b/test/install/install.bats
index 262bf4f0..b3aee5a7 100644
--- a/test/install/install.bats
+++ b/test/install/install.bats
@@ -29,7 +29,7 @@ function local_setup {
 
   assert_link_exist "$BASH_IT/enabled/150---general.aliases.bash"
   assert_link_exist "$BASH_IT/enabled/250---base.plugin.bash"
-  assert_link_exist "$BASH_IT/enabled/365---alias-completion.plugin.bash"
+  assert_link_exist "$BASH_IT/enabled/800---aliases.completion.bash"
   assert_link_exist "$BASH_IT/enabled/350---bash-it.completion.bash"
   assert_link_exist "$BASH_IT/enabled/325---system.completion.bash"
 }
diff --git a/test/lib/helpers.bats b/test/lib/helpers.bats
index bd339d04..8c340c58 100755
--- a/test/lib/helpers.bats
+++ b/test/lib/helpers.bats
@@ -296,7 +296,7 @@ function local_setup {
 
   assert_link_exist "$BASH_IT/enabled/150---general.aliases.bash"
   assert_link_exist "$BASH_IT/enabled/250---base.plugin.bash"
-  assert_link_exist "$BASH_IT/enabled/365---alias-completion.plugin.bash"
+  assert_link_exist "$BASH_IT/enabled/800---aliases.completion.bash"
   assert_link_exist "$BASH_IT/enabled/350---bash-it.completion.bash"
   assert_link_exist "$BASH_IT/enabled/325---system.completion.bash"
 }
@@ -356,7 +356,7 @@ function local_setup {
   run _bash-it-profile-load "test"
   assert_link_not_exist "$BASH_IT/enabled/150---general.aliases.bash"
   assert_link_not_exist "$BASH_IT/enabled/250---base.plugin.bash"
-  assert_link_not_exist "$BASH_IT/enabled/365---alias-completion.plugin.bash"
+  assert_link_not_exist "$BASH_IT/enabled/800---aliases.completion.bash"
   assert_link_not_exist "$BASH_IT/enabled/350---bash-it.completion.bash"
   assert_link_not_exist "$BASH_IT/enabled/325---system.completion.bash"
 }
@@ -384,7 +384,7 @@ function local_setup {
 
 @test "helpers: profile load corrupted profile file: bad subdirectory" {
   run _bash-it-profile-load "test-bad-type"
-  assert_line -n 1 -p "Bad line(#5) in profile, aborting load..."
+  assert_line -n 1 -p "Bad line(#4) in profile, aborting load..."
 }
 
 @test "helpers: profile rm sanity" {
diff --git a/test/plugins/battery.plugin.bats b/test/plugins/battery.plugin.bats
old mode 100644
new mode 100755
index eac6d021..f06fa008
--- a/test/plugins/battery.plugin.bats
+++ b/test/plugins/battery.plugin.bats
@@ -193,11 +193,26 @@ function setup_acpi {
 # Creates a `upower` function that simulates output like the real `upower` command.
 # The passed in parameter is used for the remaining battery percentage.
 function setup_upower {
-  percent="$1"
+	percent="$1"
+	BAT0="/org/freedesktop/UPower/devices/battery_BAT$RANDOM"
 
-  function upower {
-    printf "voltage:             12.191 V\n    time to full:        57.3 minutes\n    percentage:          %s\n    capacity:            84.6964" "${percent}"
-  }
+
+	function upower {
+		case $1 in
+		'-e'|'--enumerate')
+			echo "$BAT0"
+			echo "/org/freedesktop/UPower/devices/mouse_hid_${RANDOM}_battery"
+			;;
+		'-i'|'--show-info')
+			if [[ $2 == "$BAT0" ]]
+			then
+				printf "voltage:             12.191 V\n    time to full:        57.3 minutes\n    percentage:          %s\n    capacity:            84.6964" "${percent}"
+			else
+				false
+			fi
+			;;
+		esac
+	}
 }
 
 @test 'plugins battery: battery-percentage with upower, 100%' {
diff --git a/themes/base.theme.bash b/themes/base.theme.bash
index a7e99961..d7479b3f 100644
--- a/themes/base.theme.bash
+++ b/themes/base.theme.bash
@@ -584,6 +584,7 @@ function aws_profile {
 }
 
 function _save-and-reload-history() {
-	local autosave=${1:-0}
-	[[ $autosave -eq 1 ]] && history -a && history -c && history -r
+	local autosave="${1:-${HISTORY_AUTOSAVE:-0}}"
+	[[ ${autosave} -eq 1 ]] && local HISTCONTROL="${HISTCONTROL:-}${HISTCONTROL:+:}autoshare"
+	_bash-it-history-auto-save && _bash-it-history-auto-load
 }