diff --git a/clean_files.txt b/clean_files.txt
index 54180c19..15c91227 100644
--- a/clean_files.txt
+++ b/clean_files.txt
@@ -158,8 +158,10 @@ themes/candy
 themes/command_duration.theme.bash
 themes/easy
 themes/essential
+themes/githelpers.theme.bash
 themes/modern
 themes/norbu
+themes/p4helpers.theme.bash
 themes/pete
 themes/powerline
 themes/pure
diff --git a/themes/base.theme.bash b/themes/base.theme.bash
index d7479b3f..92a56e5e 100644
--- a/themes/base.theme.bash
+++ b/themes/base.theme.bash
@@ -1,16 +1,20 @@
 # shellcheck shell=bash
 # shellcheck disable=SC2034 # Expected behavior for themes.
 
+# Colors for listing files, using default color scheme.
+# To customize color scheme by theme, check out https://geoff.greer.fm/lscolors/
+export CLICOLOR LSCOLORS LS_COLORS
+
 CLOCK_CHAR_THEME_PROMPT_PREFIX=''
 CLOCK_CHAR_THEME_PROMPT_SUFFIX=''
 CLOCK_THEME_PROMPT_PREFIX=''
 CLOCK_THEME_PROMPT_SUFFIX=''
 
-THEME_PROMPT_HOST='\H'
+THEME_PROMPT_HOST='\h'
 
 SCM=
 
-SCM_CHECK=${SCM_CHECK:=true}
+: "${SCM_CHECK:=true}"
 
 SCM_THEME_PROMPT_DIRTY=' ✗'
 SCM_THEME_PROMPT_CLEAN=' ✓'
@@ -30,15 +34,15 @@ SCM_THEME_CHAR_SUFFIX=''
 : "${THEME_CHECK_SUDO:=false}"
 : "${THEME_BATTERY_PERCENTAGE_CHECK:=true}"
 
-SCM_GIT_SHOW_DETAILS=${SCM_GIT_SHOW_DETAILS:=true}
-SCM_GIT_SHOW_REMOTE_INFO=${SCM_GIT_SHOW_REMOTE_INFO:=auto}
-SCM_GIT_IGNORE_UNTRACKED=${SCM_GIT_IGNORE_UNTRACKED:=false}
-SCM_GIT_SHOW_CURRENT_USER=${SCM_GIT_SHOW_CURRENT_USER:=false}
-SCM_GIT_SHOW_MINIMAL_INFO=${SCM_GIT_SHOW_MINIMAL_INFO:=false}
-SCM_GIT_SHOW_STASH_INFO=${SCM_GIT_SHOW_STASH_INFO:=true}
-SCM_GIT_SHOW_COMMIT_COUNT=${SCM_GIT_SHOW_COMMIT_COUNT:=true}
-SCM_GIT_USE_GITSTATUS=${SCM_GIT_USE_GITSTATUS:=false}
-SCM_GIT_GITSTATUS_RAN=${SCM_GIT_GITSTATUS_RAN:=false}
+: "${SCM_GIT_SHOW_DETAILS:=true}"
+: "${SCM_GIT_SHOW_REMOTE_INFO:=auto}"
+: "${SCM_GIT_IGNORE_UNTRACKED:=false}"
+: "${SCM_GIT_SHOW_CURRENT_USER:=false}"
+: "${SCM_GIT_SHOW_MINIMAL_INFO:=false}"
+: "${SCM_GIT_SHOW_STASH_INFO:=true}"
+: "${SCM_GIT_SHOW_COMMIT_COUNT:=true}"
+: "${SCM_GIT_USE_GITSTATUS:=false}"
+: "${SCM_GIT_GITSTATUS_RAN:=false}"
 
 SCM_GIT='git'
 SCM_GIT_CHAR='±'
@@ -73,9 +77,9 @@ NVM_THEME_PROMPT_SUFFIX='|'
 RVM_THEME_PROMPT_PREFIX=' |'
 RVM_THEME_PROMPT_SUFFIX='|'
 
-THEME_SHOW_RUBY_PROMPT=${THEME_SHOW_RUBY_PROMPT:=true}
+: "${THEME_SHOW_RUBY_PROMPT:=true}"
 
-THEME_SHOW_USER_HOST=${THEME_SHOW_USER_HOST:=false}
+: "${THEME_SHOW_USER_HOST:=false}"
 USER_HOST_THEME_PROMPT_PREFIX=''
 USER_HOST_THEME_PROMPT_SUFFIX=''
 
@@ -88,154 +92,160 @@ RBENV_THEME_PROMPT_SUFFIX='|'
 RBFU_THEME_PROMPT_PREFIX=' |'
 RBFU_THEME_PROMPT_SUFFIX='|'
 
-: "${GIT_EXE:=$SCM_GIT}"
-: "${P4_EXE:=$SCM_P4}"
-: "${HG_EXE:=$SCM_HG}"
-: "${SVN_EXE:=$SCM_SVN}"
+: "${GIT_EXE:=${SCM_GIT?}}"
+: "${HG_EXE:=${SCM_HG?}}"
+: "${SVN_EXE:=${SCM_SVN?}}"
+: "${P4_EXE:=${SCM_P4?}}"
 
 function _bash_it_appearance_scm_init() {
-	GIT_EXE="$(type -P $SCM_GIT || true)"
-	P4_EXE="$(type -P $SCM_P4 || true)"
-	HG_EXE="$(type -P $SCM_HG || true)"
-	SVN_EXE="$(type -P $SCM_SVN || true)"
+	GIT_EXE="$(type -P "${SCM_GIT:-git}" || true)"
+	HG_EXE="$(type -P "${SCM_HG:-hg}" || true)"
+	SVN_EXE="$(type -P "${SCM_SVN:-svn}" || true)"
+	P4_EXE="$(type -P "${SCM_P4:-p4}" || true)"
 
 	# Check for broken SVN exe that is caused by some versions of Xcode.
 	# See https://github.com/Bash-it/bash-it/issues/1612 for more details.
-	if [[ -x "$SVN_EXE" && -x "${SVN_EXE%/*}/xcrun" ]]; then
-		if ! "$SVN_EXE" --version > /dev/null 2>&1; then
+	if [[ -x "${SVN_EXE-}" && -x "${SVN_EXE%/svn}/xcrun" ]]; then
+		if ! "${SVN_EXE}" --version > /dev/null 2>&1; then
 			# Unset the SVN exe variable so that SVN commands are avoided.
 			SVN_EXE=""
 		fi
 	fi
+	return 0
 }
 _bash_it_library_finalize_hook+=('_bash_it_appearance_scm_init')
 
-function scm {
-	if [[ "$SCM_CHECK" = false ]]; then
-		SCM=$SCM_NONE
-	elif [[ -f .git/HEAD ]] && [[ -x "$GIT_EXE" ]]; then
-		SCM=$SCM_GIT
-	elif [[ -d .hg ]] && [[ -x "$HG_EXE" ]]; then
-		SCM=$SCM_HG
-	elif [[ -d .svn ]] && [[ -x "$SVN_EXE" ]]; then
-		SCM=$SCM_SVN
-	elif [[ -x "$GIT_EXE" ]] && [[ -n "$(git rev-parse --is-inside-work-tree 2> /dev/null)" ]]; then
-		SCM=$SCM_GIT
-	elif [[ -x "$HG_EXE" ]] && [[ -n "$(hg root 2> /dev/null)" ]]; then
-		SCM=$SCM_HG
-	elif [[ -x "$SVN_EXE" ]] && [[ -n "$(svn info --show-item wc-root 2> /dev/null)" ]]; then
-		SCM=$SCM_SVN
-	elif [[ -x "$P4_EXE" ]] && [[ -n "$(p4 set P4CLIENT 2> /dev/null)" ]]; then
-		SCM=$SCM_P4
+function scm() {
+	if [[ "${SCM_CHECK:-true}" == "false" ]]; then
+		SCM="${SCM_NONE-NONE}"
+	elif [[ -x "${GIT_EXE-}" ]] && _bash-it-find-in-ancestor '.git' > /dev/null; then
+		SCM="${SCM_GIT?}"
+	elif [[ -x "${HG_EXE-}" ]] && _bash-it-find-in-ancestor '.hg' > /dev/null; then
+		SCM="${SCM_HG?}"
+	elif [[ -x "${SVN_EXE-}" ]] && _bash-it-find-in-ancestor '.svn' > /dev/null; then
+		SCM="${SCM_SVN?}"
+	elif [[ -x "${P4_EXE-}" && -n "$(p4 set P4CLIENT 2> /dev/null)" ]]; then
+		SCM="${SCM_P4?}"
 	else
-		SCM=$SCM_NONE
+		SCM="${SCM_NONE-NONE}"
 	fi
 }
 
-scm_prompt() {
-	local CHAR
-	CHAR="$(scm_char)"
-	local format=${SCM_PROMPT_FORMAT:-'[%s%s]'}
+function scm_prompt() {
+	local format="${SCM_PROMPT_FORMAT-"[%s%s]"}"
+	local scm_char scm_prompt_info
+	scm_char="$(scm_char)"
+	scm_prompt_info="$(scm_prompt_info)"
 
-	if [[ "${CHAR}" != "$SCM_NONE_CHAR" ]]; then
+	if [[ "${scm_char}" != "${SCM_NONE_CHAR:-}" ]]; then
 		# shellcheck disable=2059
-		printf "$format\n" "$CHAR" "$(scm_prompt_info)"
+		printf "${format}" "${scm_char}" "${scm_prompt_info}"
 	fi
 }
 
-function scm_prompt_char {
-	if [[ -z $SCM ]]; then scm; fi
-	if [[ $SCM == "$SCM_GIT" ]]; then
-		SCM_CHAR=$SCM_GIT_CHAR
-	elif [[ $SCM == "$SCM_P4" ]]; then
-		SCM_CHAR=$SCM_P4_CHAR
-	elif [[ $SCM == "$SCM_HG" ]]; then
-		SCM_CHAR=$SCM_HG_CHAR
-	elif [[ $SCM == "$SCM_SVN" ]]; then
-		SCM_CHAR=$SCM_SVN_CHAR
-	else
-		SCM_CHAR=$SCM_NONE_CHAR
+function scm_prompt_char() {
+	if [[ -z "${SCM:-}" ]]; then
+		scm
 	fi
+
+	case ${SCM?} in
+		"${SCM_GIT?}")
+			SCM_CHAR="${SCM_GIT_CHAR?}"
+			;;
+		"${SCM_HG?}")
+			SCM_CHAR="${SCM_HG_CHAR?}"
+			;;
+		"${SCM_SVN?}")
+			SCM_CHAR="${SCM_SVN_CHAR?}"
+			;;
+		"${SCM_P4?}")
+			SCM_CHAR="${SCM_P4_CHAR?}"
+			;;
+		*)
+			SCM_CHAR="${SCM_NONE_CHAR:-}"
+			;;
+	esac
 }
 
-function scm_prompt_vars {
+function scm_prompt_vars() {
 	scm
 	scm_prompt_char
 	SCM_DIRTY=0
 	SCM_STATE=''
-	[[ $SCM == "$SCM_GIT" ]] && git_prompt_vars && return
-	[[ $SCM == "$SCM_P4" ]] && p4_prompt_vars && return
-	[[ $SCM == "$SCM_HG" ]] && hg_prompt_vars && return
-	[[ $SCM == "$SCM_SVN" ]] && svn_prompt_vars && return
+
+	local prompt_vars="${SCM}_prompt_vars"
+	_is_function "${prompt_vars}" && "${prompt_vars}"
 }
 
-function scm_prompt_info {
+function scm_prompt_info() {
 	scm
 	scm_prompt_char
 	scm_prompt_info_common
 }
 
-function scm_prompt_char_info {
+function scm_prompt_char_info() {
 	scm_prompt_char
-	echo -ne "${SCM_THEME_CHAR_PREFIX}${SCM_CHAR}${SCM_THEME_CHAR_SUFFIX}"
+	echo -ne "${SCM_THEME_CHAR_PREFIX-}${SCM_CHAR?}${SCM_THEME_CHAR_SUFFIX-}"
 	scm_prompt_info_common
 }
 
-function scm_prompt_info_common {
+function scm_prompt_info_common() {
+	local prompt_info
 	SCM_DIRTY=0
 	SCM_STATE=''
 
-	if [[ ${SCM} == "${SCM_GIT}" ]]; then
-		if [[ ${SCM_GIT_SHOW_MINIMAL_INFO} == true ]]; then
-			# user requests minimal git status information
-			git_prompt_minimal_info
-		else
-			# more detailed git status
-			git_prompt_info
-		fi
-		return
-	fi
-
-	# TODO: consider adding minimal status information for hg and svn
-	{ [[ ${SCM} == "${SCM_P4}" ]] && p4_prompt_info && return; } || true
-	{ [[ ${SCM} == "${SCM_HG}" ]] && hg_prompt_info && return; } || true
-	{ [[ ${SCM} == "${SCM_SVN}" ]] && svn_prompt_info && return; } || true
+	case ${SCM?} in
+		"${SCM_GIT?}")
+			if [[ ${SCM_GIT_SHOW_MINIMAL_INFO:-false} == "true" ]]; then
+				# user requests minimal git status information
+				prompt_info="${SCM}_prompt_minimal_info"
+			else
+				# more detailed git status
+				prompt_info="${SCM}_prompt_info"
+			fi
+			;;
+		*)
+			# TODO: consider adding minimal status information for hg and svn
+			prompt_info="${SCM}_prompt_info"
+			;;
+	esac
+	_is_function "${prompt_info}" && "${prompt_info}"
 }
 
-function terraform_workspace_prompt {
+function terraform_workspace_prompt() {
 	if _command_exists terraform; then
-		if [ -d .terraform ]; then
-			echo -e "$(terraform workspace show 2> /dev/null)"
+		if [[ -d .terraform ]]; then
+			terraform workspace show 2> /dev/null
 		fi
 	fi
 }
 
-function active_gcloud_account_prompt {
+function active_gcloud_account_prompt() {
 	if _command_exists gcloud; then
-		echo -e "$(gcloud config list account --format "value(core.account)" 2> /dev/null)"
+		gcloud config list account --format "value(core.account)" 2> /dev/null
 	fi
 }
 
-function git_prompt_minimal_info {
-	SCM_STATE=${SCM_THEME_PROMPT_CLEAN}
+function git_prompt_minimal_info() {
+	SCM_STATE="${SCM_THEME_PROMPT_CLEAN?}"
 
 	_git-hide-status && return
 
-	SCM_BRANCH="${SCM_THEME_BRANCH_PREFIX}\$(_git-friendly-ref)"
+	SCM_BRANCH="${SCM_THEME_BRANCH_PREFIX-}\$(_git-friendly-ref)"
 
 	if [[ -n "$(_git-status | tail -n1)" ]]; then
 		SCM_DIRTY=1
-		SCM_STATE=${SCM_THEME_PROMPT_DIRTY}
+		SCM_STATE="${SCM_THEME_PROMPT_DIRTY?}"
 	fi
 
 	# Output the git prompt
-	SCM_PREFIX=${SCM_THEME_PROMPT_PREFIX}
-	SCM_SUFFIX=${SCM_THEME_PROMPT_SUFFIX}
-	echo -e "${SCM_PREFIX}${SCM_BRANCH}${SCM_STATE}${SCM_SUFFIX}"
+	SCM_PREFIX="${SCM_THEME_PROMPT_PREFIX-}"
+	SCM_SUFFIX="${SCM_THEME_PROMPT_SUFFIX-}"
+	echo -ne "${SCM_PREFIX}${SCM_BRANCH}${SCM_STATE}${SCM_SUFFIX}"
 }
 
-function git_prompt_vars {
-	if ${SCM_GIT_USE_GITSTATUS} && _command_exists gitstatus_query && gitstatus_query && [[ "${VCS_STATUS_RESULT}" == "ok-sync" ]]; then
+function git_prompt_vars() {
+	if [[ "${SCM_GIT_USE_GITSTATUS:-false}" != "false" ]] && _command_exists gitstatus_query && gitstatus_query && [[ "${VCS_STATUS_RESULT:-}" == "ok-sync" ]]; then
 		# we can use faster gitstatus
 		# use this variable in githelpers and below to choose gitstatus output
 		SCM_GIT_GITSTATUS_RAN=true
@@ -251,190 +261,174 @@ function git_prompt_vars {
 
 		local detached_prefix
 		if _git-tag &> /dev/null; then
-			detached_prefix=${SCM_THEME_TAG_PREFIX}
+			detached_prefix="${SCM_THEME_TAG_PREFIX}"
 		else
-			detached_prefix=${SCM_THEME_DETACHED_PREFIX}
+			detached_prefix="${SCM_THEME_DETACHED_PREFIX}"
 		fi
 		SCM_BRANCH="${detached_prefix}\$(_git-friendly-ref)"
 	fi
 
-	if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-		commits_behind=${VCS_STATUS_COMMITS_BEHIND}
-		commits_ahead=${VCS_STATUS_COMMITS_AHEAD}
+	if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+		commits_behind="${VCS_STATUS_COMMITS_BEHIND?}"
+		commits_ahead="${VCS_STATUS_COMMITS_AHEAD?}"
 	else
 		IFS=$'\t' read -r commits_behind commits_ahead <<< "$(_git-upstream-behind-ahead)"
 	fi
 	if [[ "${commits_ahead}" -gt 0 ]]; then
 		SCM_BRANCH+="${SCM_GIT_AHEAD_BEHIND_PREFIX_CHAR}${SCM_GIT_AHEAD_CHAR}"
-		[[ "${SCM_GIT_SHOW_COMMIT_COUNT}" = "true" ]] && SCM_BRANCH+="${commits_ahead}"
+		[[ "${SCM_GIT_SHOW_COMMIT_COUNT}" == "true" ]] && SCM_BRANCH+="${commits_ahead}"
 	fi
 	if [[ "${commits_behind}" -gt 0 ]]; then
 		SCM_BRANCH+="${SCM_GIT_AHEAD_BEHIND_PREFIX_CHAR}${SCM_GIT_BEHIND_CHAR}"
-		[[ "${SCM_GIT_SHOW_COMMIT_COUNT}" = "true" ]] && SCM_BRANCH+="${commits_behind}"
+		[[ "${SCM_GIT_SHOW_COMMIT_COUNT}" == "true" ]] && SCM_BRANCH+="${commits_behind}"
 	fi
 
-	if [[ "${SCM_GIT_SHOW_STASH_INFO}" = "true" ]]; then
+	if [[ "${SCM_GIT_SHOW_STASH_INFO}" == "true" ]]; then
 		local stash_count
 		if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-			stash_count=${VCS_STATUS_STASHES}
+			stash_count="${VCS_STATUS_STASHES?}"
 		else
 			stash_count="$(git stash list 2> /dev/null | wc -l | tr -d ' ')"
 		fi
 		[[ "${stash_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_GIT_STASH_CHAR_PREFIX}${stash_count}${SCM_GIT_STASH_CHAR_SUFFIX}"
 	fi
 
-	SCM_STATE=${GIT_THEME_PROMPT_CLEAN:-$SCM_THEME_PROMPT_CLEAN}
+	SCM_STATE="${GIT_THEME_PROMPT_CLEAN:-${SCM_THEME_PROMPT_CLEAN:-}}"
 	if ! _git-hide-status; then
-		if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-			untracked_count=${VCS_STATUS_NUM_UNTRACKED}
-			unstaged_count=${VCS_STATUS_NUM_UNSTAGED}
-			staged_count=${VCS_STATUS_NUM_STAGED}
+		if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+			untracked_count="${VCS_STATUS_NUM_UNTRACKED?}"
+			unstaged_count="${VCS_STATUS_NUM_UNSTAGED?}"
+			staged_count="${VCS_STATUS_NUM_STAGED?}"
 		else
-			IFS=$'\t' read -r untracked_count unstaged_count staged_count <<< "$(_git-status-counts)"
+			IFS=$'\t' read -r untracked_count unstaged_count staged_count < <(_git-status-counts)
 		fi
 		if [[ "${untracked_count}" -gt 0 || "${unstaged_count}" -gt 0 || "${staged_count}" -gt 0 ]]; then
 			SCM_DIRTY=1
-			if [[ "${SCM_GIT_SHOW_DETAILS}" = "true" ]]; then
+			if [[ "${SCM_GIT_SHOW_DETAILS}" == "true" ]]; then
 				[[ "${staged_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_GIT_STAGED_CHAR}${staged_count}" && SCM_DIRTY=3
 				[[ "${unstaged_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_GIT_UNSTAGED_CHAR}${unstaged_count}" && SCM_DIRTY=2
 				[[ "${untracked_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_GIT_UNTRACKED_CHAR}${untracked_count}" && SCM_DIRTY=1
 			fi
-			SCM_STATE=${GIT_THEME_PROMPT_DIRTY:-$SCM_THEME_PROMPT_DIRTY}
+			SCM_STATE="${GIT_THEME_PROMPT_DIRTY:-${SCM_THEME_PROMPT_DIRTY?}}"
 		fi
 	fi
 
 	# no if for gitstatus here, user extraction is not supported by it
 	[[ "${SCM_GIT_SHOW_CURRENT_USER}" == "true" ]] && SCM_BRANCH+="$(git_user_info)"
 
-	SCM_PREFIX=${GIT_THEME_PROMPT_PREFIX:-$SCM_THEME_PROMPT_PREFIX}
-	SCM_SUFFIX=${GIT_THEME_PROMPT_SUFFIX:-$SCM_THEME_PROMPT_SUFFIX}
+	SCM_PREFIX="${GIT_THEME_PROMPT_PREFIX:-${SCM_THEME_PROMPT_PREFIX-}}"
+	SCM_SUFFIX="${GIT_THEME_PROMPT_SUFFIX:-${SCM_THEME_PROMPT_SUFFIX-}}"
 
-	SCM_CHANGE=$(_git-short-sha 2> /dev/null || echo "")
+	SCM_CHANGE=$(_git-short-sha 2> /dev/null || true)
 }
 
-function p4_prompt_vars {
+function p4_prompt_vars() {
+	local opened_count non_default_changes default_count \
+		add_file_count edit_file_count delete_file_count
+
 	IFS=$'\t' read -r \
 		opened_count non_default_changes default_count \
 		add_file_count edit_file_count delete_file_count \
-		<<< "$(_p4-opened-counts)"
+		< <(_p4-opened-counts)
 	if [[ "${opened_count}" -gt 0 ]]; then
 		SCM_DIRTY=1
-		SCM_STATE=${SCM_THEME_PROMPT_DIRTY}
-		[[ "${opened_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_P4_OPENED_CHAR}${opened_count}"
-		[[ "${non_default_changes}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_P4_CHANGES_CHAR}${non_default_changes}"
-		[[ "${default_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_P4_DEFAULT_CHAR}${default_count}"
+		SCM_STATE="${SCM_THEME_PROMPT_DIRTY?}"
+		[[ "${opened_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_P4_OPENED_CHAR?}${opened_count}"
+		[[ "${non_default_changes}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_P4_CHANGES_CHAR?}${non_default_changes}"
+		[[ "${default_count}" -gt 0 ]] && SCM_BRANCH+=" ${SCM_P4_DEFAULT_CHAR?}${default_count}"
 	else
 		SCM_DIRTY=0
-		SCM_STATE=${SCM_THEME_PROMPT_DIRTY}
+		SCM_STATE="${SCM_THEME_PROMPT_CLEAN?}"
 	fi
 
-	SCM_PREFIX=${P4_THEME_PROMPT_PREFIX:-$SCM_THEME_PROMPT_PREFIX}
-	SCM_SUFFIX=${P4_THEME_PROMPT_SUFFIX:-$SCM_THEME_PROMPT_SUFFIX}
+	SCM_PREFIX="${P4_THEME_PROMPT_PREFIX:-${SCM_THEME_PROMPT_PREFIX-}}"
+	SCM_SUFFIX="${P4_THEME_PROMPT_SUFFIX:-${SCM_THEME_PROMPT_SUFFIX-}}"
 }
 
-function svn_prompt_vars {
-	if [[ -n $(svn status | head -c1 2> /dev/null) ]]; then
+function svn_prompt_vars() {
+	if [[ -n "$(svn status | head -c1 2> /dev/null)" ]]; then
 		SCM_DIRTY=1
-		SCM_STATE=${SVN_THEME_PROMPT_DIRTY:-$SCM_THEME_PROMPT_DIRTY}
+		SCM_STATE="${SVN_THEME_PROMPT_DIRTY:-${SCM_THEME_PROMPT_DIRTY?}}"
 	else
 		SCM_DIRTY=0
-		SCM_STATE=${SVN_THEME_PROMPT_CLEAN:-$SCM_THEME_PROMPT_CLEAN}
+		SCM_STATE="${SVN_THEME_PROMPT_CLEAN:-${SCM_THEME_PROMPT_CLEAN?}}"
 	fi
-	SCM_PREFIX=${SVN_THEME_PROMPT_PREFIX:-$SCM_THEME_PROMPT_PREFIX}
-	SCM_SUFFIX=${SVN_THEME_PROMPT_SUFFIX:-$SCM_THEME_PROMPT_SUFFIX}
-	SCM_BRANCH=$(svn info --show-item=url 2> /dev/null | awk -F/ '{ for (i=0; i<=NF; i++) { if ($i == "branches" || $i == "tags" ) { print $(i+1); break }; if ($i == "trunk") { print $i; break } } }') || return
-	SCM_CHANGE=$(svn info --show-item=revision 2> /dev/null)
+	SCM_PREFIX="${SVN_THEME_PROMPT_PREFIX:-${SCM_THEME_PROMPT_PREFIX-}}"
+	SCM_SUFFIX="${SVN_THEME_PROMPT_SUFFIX:-${SCM_THEME_PROMPT_SUFFIX-}}"
+	SCM_BRANCH="$(svn info --show-item=url 2> /dev/null | awk -F/ '{ for (i=0; i<=NF; i++) { if ($i == "branches" || $i == "tags" ) { print $(i+1); break }; if ($i == "trunk") { print $i; break } } }')" || return
+	SCM_CHANGE="$(svn info --show-item=revision 2> /dev/null)"
 }
 
-# this functions returns absolute location of .hg directory if one exists
-# It starts in the current directory and moves its way up until it hits /.
-# If we get to / then no Mercurial repository was found.
-# Example:
-# - lets say we cd into ~/Projects/Foo/Bar
-# - .hg is located in ~/Projects/Foo/.hg
-# - get_hg_root starts at ~/Projects/Foo/Bar and sees that there is no .hg directory, so then it goes into ~/Projects/Foo
-function get_hg_root {
-	local CURRENT_DIR="${PWD}"
-
-	while [[ "${CURRENT_DIR:-/}" != "/" ]]; do
-		if [[ -d "$CURRENT_DIR/.hg" ]]; then
-			echo "$CURRENT_DIR/.hg"
-			return
-		fi
-
-		CURRENT_DIR="${CURRENT_DIR%/*}"
-	done
-}
-
-function hg_prompt_vars {
+function hg_prompt_vars() {
+	local hg_root bookmark
 	if [[ -n $(hg status 2> /dev/null) ]]; then
 		SCM_DIRTY=1
-		SCM_STATE=${HG_THEME_PROMPT_DIRTY:-$SCM_THEME_PROMPT_DIRTY}
+		SCM_STATE="${HG_THEME_PROMPT_DIRTY:-${SCM_THEME_PROMPT_DIRTY?}}"
 	else
 		SCM_DIRTY=0
-		SCM_STATE=${HG_THEME_PROMPT_CLEAN:-$SCM_THEME_PROMPT_CLEAN}
+		SCM_STATE="${HG_THEME_PROMPT_CLEAN:-${SCM_THEME_PROMPT_CLEAN?}}"
 	fi
-	SCM_PREFIX=${HG_THEME_PROMPT_PREFIX:-$SCM_THEME_PROMPT_PREFIX}
-	SCM_SUFFIX=${HG_THEME_PROMPT_SUFFIX:-$SCM_THEME_PROMPT_SUFFIX}
+	SCM_PREFIX="${HG_THEME_PROMPT_PREFIX:-${SCM_THEME_PROMPT_PREFIX-}}"
+	SCM_SUFFIX="${HG_THEME_PROMPT_SUFFIX:-${SCM_THEME_PROMPT_SUFFIX-}}"
 
-	HG_ROOT=$(get_hg_root)
+	hg_root="$(_bash-it-find-in-ancestor ".hg")/.hg"
 
-	if [ -f "$HG_ROOT/branch" ]; then
+	if [[ -f "$hg_root/branch" ]]; then
 		# Mercurial holds it's current branch in .hg/branch file
-		SCM_BRANCH=$(< "${HG_ROOT}/branch")
-		local bookmark=${HG_ROOT}/bookmarks.current
-		[[ -f ${bookmark} ]] && SCM_BRANCH+=:$(< "${bookmark}")
+		SCM_BRANCH=$(< "${hg_root}/branch")
+		bookmark="${hg_root}/bookmarks.current"
+		[[ -f "${bookmark}" ]] && SCM_BRANCH+=:$(< "${bookmark}")
 	else
 		SCM_BRANCH=$(hg summary 2> /dev/null | grep branch: | awk '{print $2}')
 	fi
 
-	if [ -f "$HG_ROOT/dirstate" ]; then
+	if [[ -f "$hg_root/dirstate" ]]; then
 		# Mercurial holds various information about the working directory in .hg/dirstate file. More on http://mercurial.selenic.com/wiki/DirState
-		SCM_CHANGE=$(hexdump -vn 10 -e '1/1 "%02x"' "$HG_ROOT/dirstate" | cut -c-12)
+		SCM_CHANGE=$(hexdump -vn 10 -e '1/1 "%02x"' "$hg_root/dirstate" | cut -c-12)
 	else
 		SCM_CHANGE=$(hg summary 2> /dev/null | grep parent: | awk '{print $2}')
 	fi
 }
 
-function nvm_version_prompt {
+function nvm_version_prompt() {
 	local node
 	if _is_function nvm; then
 		node=$(nvm current 2> /dev/null)
 		[[ "${node}" == "system" ]] && return
-		echo -e "${NVM_THEME_PROMPT_PREFIX}${node}${NVM_THEME_PROMPT_SUFFIX}"
+		echo -ne "${NVM_THEME_PROMPT_PREFIX-}${node}${NVM_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function node_version_prompt {
-	echo -e "$(nvm_version_prompt)"
+function node_version_prompt() {
+	nvm_version_prompt
 }
 
-function rvm_version_prompt {
-	if which rvm &> /dev/null; then
-		rvm=$(rvm-prompt) || return
-		if [ -n "$rvm" ]; then
-			echo -e "$RVM_THEME_PROMPT_PREFIX$rvm$RVM_THEME_PROMPT_SUFFIX"
+function rvm_version_prompt() {
+	if _command_exists rvm; then
+		rvm="$(rvm-prompt)" || return
+		if [[ -n "$rvm" ]]; then
+			echo -ne "${RVM_THEME_PROMPT_PREFIX-}${rvm}${RVM_THEME_PROMPT_SUFFIX-}"
 		fi
 	fi
 }
 
-function rbenv_version_prompt {
-	if which rbenv &> /dev/null; then
+function rbenv_version_prompt() {
+	if _command_exists rbenv; then
 		rbenv=$(rbenv version-name) || return
 		rbenv commands | grep -q gemset && gemset=$(rbenv gemset active 2> /dev/null) && rbenv="$rbenv@${gemset%% *}"
-		if [ "$rbenv" != "system" ]; then
-			echo -e "$RBENV_THEME_PROMPT_PREFIX$rbenv$RBENV_THEME_PROMPT_SUFFIX"
+		if [[ "$rbenv" != "system" ]]; then
+			echo -ne "${RBENV_THEME_PROMPT_PREFIX-}${rbenv}${RBENV_THEME_PROMPT_SUFFIX-}"
 		fi
 	fi
 }
 
-function rbfu_version_prompt {
-	if [[ $RBFU_RUBY_VERSION ]]; then
-		echo -e "${RBFU_THEME_PROMPT_PREFIX}${RBFU_RUBY_VERSION}${RBFU_THEME_PROMPT_SUFFIX}"
+function rbfu_version_prompt() {
+	if [[ -n "${RBFU_RUBY_VERSION:-}" ]]; then
+		echo -ne "${RBFU_THEME_PROMPT_PREFIX-}${RBFU_RUBY_VERSION}${RBFU_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function chruby_version_prompt {
+function chruby_version_prompt() {
 	if _is_function chruby; then
 		if _is_function chruby_auto; then
 			chruby_auto
@@ -445,141 +439,142 @@ function chruby_version_prompt {
 		if ! chruby | grep -q '\*'; then
 			ruby_version="${ruby_version} (system)"
 		fi
-		echo -e "${CHRUBY_THEME_PROMPT_PREFIX}${ruby_version}${CHRUBY_THEME_PROMPT_SUFFIX}"
+		echo -ne "${CHRUBY_THEME_PROMPT_PREFIX-}${ruby_version}${CHRUBY_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function ruby_version_prompt {
-	if [[ "${THEME_SHOW_RUBY_PROMPT}" = "true" ]]; then
-		echo -e "$(rbfu_version_prompt)$(rbenv_version_prompt)$(rvm_version_prompt)$(chruby_version_prompt)"
+function ruby_version_prompt() {
+	if [[ "${THEME_SHOW_RUBY_PROMPT:-}" == "true" ]]; then
+		rbfu_version_prompt
+		rbenv_version_prompt
+		rvm_version_prompt
+		chruby_version_prompt
 	fi
 }
 
-function k8s_context_prompt {
-	echo -e "$(kubectl config current-context 2> /dev/null)"
+function k8s_context_prompt() {
+	kubectl config current-context 2> /dev/null
 }
 
-function k8s_namespace_prompt {
-	echo -e "$(kubectl config view --minify --output 'jsonpath={..namespace}' 2> /dev/null)"
+function k8s_namespace_prompt() {
+	kubectl config view --minify --output 'jsonpath={..namespace}' 2> /dev/null
 }
 
-function virtualenv_prompt {
-	if [[ -n "$VIRTUAL_ENV" ]]; then
-		virtualenv=$(basename "$VIRTUAL_ENV")
-		echo -e "$VIRTUALENV_THEME_PROMPT_PREFIX$virtualenv$VIRTUALENV_THEME_PROMPT_SUFFIX"
+function virtualenv_prompt() {
+	local virtualenv
+	if [[ -n "${VIRTUAL_ENV:-}" ]]; then
+		virtualenv="${VIRTUAL_ENV##*/}"
+		echo -ne "${VIRTUALENV_THEME_PROMPT_PREFIX-}${virtualenv}${VIRTUALENV_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function condaenv_prompt {
-	if [[ $CONDA_DEFAULT_ENV ]]; then
-		echo -e "${CONDAENV_THEME_PROMPT_PREFIX}${CONDA_DEFAULT_ENV}${CONDAENV_THEME_PROMPT_SUFFIX}"
+function condaenv_prompt() {
+	if [[ -n "${CONDA_DEFAULT_ENV:-}" ]]; then
+		echo -ne "${CONDAENV_THEME_PROMPT_PREFIX-}${CONDA_DEFAULT_ENV}${CONDAENV_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function py_interp_prompt {
-	py_version=$(python --version 2>&1 | awk 'NR==1{print "py-"$2;}') || return
-	echo -e "${PYTHON_THEME_PROMPT_PREFIX}${py_version}${PYTHON_THEME_PROMPT_SUFFIX}"
+function py_interp_prompt() {
+	local py_version
+	py_version="$(python --version 2>&1 | awk 'NR==1{print "py-"$2;}')" || return
+	echo -ne "${PYTHON_THEME_PROMPT_PREFIX-}${py_version}${PYTHON_THEME_PROMPT_SUFFIX-}"
 }
 
-function python_version_prompt {
-	echo -e "$(virtualenv_prompt)$(condaenv_prompt)$(py_interp_prompt)"
+function python_version_prompt() {
+	virtualenv_prompt
+	condaenv_prompt
+	py_interp_prompt
 }
 
-function git_user_info {
+function git_user_info() {
+	local current_user
 	# support two or more initials, set by 'git pair' plugin
-	SCM_CURRENT_USER=$(git config user.initials | sed 's% %+%')
+	current_user="$(git config user.initials | sed 's% %+%')"
 	# if `user.initials` weren't set, attempt to extract initials from `user.name`
-	[[ -z "${SCM_CURRENT_USER}" ]] && SCM_CURRENT_USER=$(printf "%s" "$(for word in $(git config user.name | PERLIO=:utf8 perl -pe '$_=lc'); do printf "%s" "${word:0:1}"; done)")
-	[[ -n "${SCM_CURRENT_USER}" ]] && printf "%s" "$SCM_THEME_CURRENT_USER_PREFFIX$SCM_CURRENT_USER$SCM_THEME_CURRENT_USER_SUFFIX"
+	[[ -z "${current_user}" ]] && current_user=$(printf "%s" "$(for word in $(git config user.name | PERLIO=:utf8 perl -pe '$_=lc'); do printf "%s" "${word:0:1}"; done)")
+	[[ -n "${current_user}" ]] && printf "%s" "${SCM_THEME_CURRENT_USER_PREFFIX-}${current_user}${SCM_THEME_CURRENT_USER_SUFFIX-}"
 }
 
-function clock_char {
-	CLOCK_CHAR=${THEME_CLOCK_CHAR:-"⌚"}
-	CLOCK_CHAR_COLOR=${THEME_CLOCK_CHAR_COLOR:-"$normal"}
-	SHOW_CLOCK_CHAR=${THEME_SHOW_CLOCK_CHAR:-"true"}
+function clock_char() {
+	local clock_char clock_char_color show_clock_char
+	clock_char="${THEME_CLOCK_CHAR:-⌚}"
+	clock_char_color="${THEME_CLOCK_CHAR_COLOR:-${normal:-}}"
+	show_clock_char="${THEME_SHOW_CLOCK_CHAR:-"true"}"
 
-	if [[ "${SHOW_CLOCK_CHAR}" = "true" ]]; then
-		echo -e "${CLOCK_CHAR_COLOR}${CLOCK_CHAR_THEME_PROMPT_PREFIX}${CLOCK_CHAR}${CLOCK_CHAR_THEME_PROMPT_SUFFIX}"
+	if [[ "${show_clock_char}" == "true" ]]; then
+		echo -ne "${clock_char_color}${CLOCK_CHAR_THEME_PROMPT_PREFIX-}${clock_char}${CLOCK_CHAR_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function clock_prompt {
-	CLOCK_COLOR=${THEME_CLOCK_COLOR:-"$normal"}
-	CLOCK_FORMAT=${THEME_CLOCK_FORMAT:-"%H:%M:%S"}
-	[ -z "$THEME_SHOW_CLOCK" ] && THEME_SHOW_CLOCK=${THEME_CLOCK_CHECK:-"true"}
-	SHOW_CLOCK=$THEME_SHOW_CLOCK
+function clock_prompt() {
+	local clock_color="${THEME_CLOCK_COLOR:-${normal?}}"
+	local clock_format="${THEME_CLOCK_FORMAT:-"%H:%M:%S"}"
+	local show_clock="${THEME_SHOW_CLOCK:-${THEME_CLOCK_CHECK:-true}}"
+	local clock_string="\D{${clock_format}}"
 
-	if [[ "${SHOW_CLOCK}" = "true" ]]; then
-		CLOCK_STRING=$(date +"${CLOCK_FORMAT}")
-		echo -e "${CLOCK_COLOR}${CLOCK_THEME_PROMPT_PREFIX}${CLOCK_STRING}${CLOCK_THEME_PROMPT_SUFFIX}"
+	if [[ "${show_clock}" == "true" ]]; then
+		echo -ne "${clock_color}${CLOCK_THEME_PROMPT_PREFIX-}${clock_string}${CLOCK_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
-function user_host_prompt {
-	if [[ "${THEME_SHOW_USER_HOST}" = "true" ]]; then
-		echo -e "${USER_HOST_THEME_PROMPT_PREFIX}\u@\h${USER_HOST_THEME_PROMPT_SUFFIX}"
+function user_host_prompt() {
+	if [[ "${THEME_SHOW_USER_HOST:-false}" == "true" ]]; then
+		echo -ne "${USER_HOST_THEME_PROMPT_PREFIX-}\u@${THEME_PROMPT_HOST:-\h}${USER_HOST_THEME_PROMPT_SUFFIX-}"
 	fi
 }
 
 # backwards-compatibility
-function git_prompt_info {
+function git_prompt_info() {
 	_git-hide-status && return
 	git_prompt_vars
-	echo -e "${SCM_PREFIX}${SCM_BRANCH}${SCM_STATE}${SCM_SUFFIX}"
+	echo -ne "${SCM_PREFIX?}${SCM_BRANCH?}${SCM_STATE?}${SCM_SUFFIX?}"
 }
 
 function p4_prompt_info() {
 	p4_prompt_vars
-	echo -e "${SCM_PREFIX}${SCM_BRANCH}:${SCM_CHANGE}${SCM_STATE}${SCM_SUFFIX}"
+	echo -ne "${SCM_PREFIX?}${SCM_BRANCH?}:${SCM_CHANGE?}${SCM_STATE?}${SCM_SUFFIX?}"
 }
 
-function svn_prompt_info {
+function svn_prompt_info() {
 	svn_prompt_vars
-	echo -e "${SCM_PREFIX}${SCM_BRANCH}${SCM_STATE}${SCM_SUFFIX}"
+	echo -ne "${SCM_PREFIX?}${SCM_BRANCH?}${SCM_STATE?}${SCM_SUFFIX?}"
 }
 
 function hg_prompt_info() {
 	hg_prompt_vars
-	echo -e "${SCM_PREFIX}${SCM_BRANCH}:${SCM_CHANGE#*:}${SCM_STATE}${SCM_SUFFIX}"
+	echo -ne "${SCM_PREFIX?}${SCM_BRANCH?}:${SCM_CHANGE#*:}${SCM_STATE?}${SCM_SUFFIX?}"
 }
 
-function scm_char {
+function scm_char() {
 	scm_prompt_char
-	echo -e "${SCM_THEME_CHAR_PREFIX}${SCM_CHAR}${SCM_THEME_CHAR_SUFFIX}"
+	echo -ne "${SCM_THEME_CHAR_PREFIX?}${SCM_CHAR?}${SCM_THEME_CHAR_SUFFIX?}"
 }
 
-function prompt_char {
+function prompt_char() {
 	scm_char
 }
 
-function battery_char {
-	if [[ "${THEME_BATTERY_PERCENTAGE_CHECK}" = true ]]; then
-		echo -e "${bold_red:-}$(battery_percentage)%"
+function battery_char() {
+	# The battery_char function depends on the presence of the battery_percentage function.
+	if [[ "${THEME_BATTERY_PERCENTAGE_CHECK}" == true ]] && _command_exists battery_percentage; then
+		echo -ne "${bold_red?}$(battery_percentage)%"
+	else
+		false
 	fi
 }
 
 if ! _command_exists battery_charge; then
 	# if user has installed battery plugin, skip this...
 	function battery_charge() {
-		# no op
-		echo -n
+		: # no op
 	}
 fi
 
-# The battery_char function depends on the presence of the battery_percentage function.
-# If battery_percentage is not defined, then define battery_char as a no-op.
-if ! _command_exists battery_percentage; then
-	function battery_char() {
-		# no op
-		echo -n
-	}
-fi
-
-function aws_profile {
-	if [[ $AWS_DEFAULT_PROFILE ]]; then
-		echo -e "${AWS_DEFAULT_PROFILE}"
+function aws_profile() {
+	if [[ -n "${AWS_DEFAULT_PROFILE:-}" ]]; then
+		echo -ne "${AWS_DEFAULT_PROFILE}"
 	else
-		echo -e "default"
+		echo -ne "default"
 	fi
 }
 
diff --git a/themes/githelpers.theme.bash b/themes/githelpers.theme.bash
index 5ef18e9a..719effec 100644
--- a/themes/githelpers.theme.bash
+++ b/themes/githelpers.theme.bash
@@ -1,99 +1,106 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
 
-function _git-symbolic-ref {
- git symbolic-ref -q HEAD 2> /dev/null
+function _git-symbolic-ref() {
+	git symbolic-ref -q HEAD 2> /dev/null
 }
 
 # When on a branch, this is often the same as _git-commit-description,
 # but this can be different when two branches are pointing to the
 # same commit. _git-branch is used to explicitly choose the checked-out
 # branch.
-function _git-branch {
-  if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-    test -n "${VCS_STATUS_LOCAL_BRANCH}" && echo "${VCS_STATUS_LOCAL_BRANCH}" || return 1
-  else
-    git symbolic-ref -q --short HEAD 2> /dev/null || return 1
-  fi
+function _git-branch() {
+	if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+		if [[ -n "${VCS_STATUS_LOCAL_BRANCH:-}" ]]; then
+			echo "${VCS_STATUS_LOCAL_BRANCH}"
+		else
+			return 1
+		fi
+	else
+		git symbolic-ref -q --short HEAD 2> /dev/null || return 1
+	fi
 }
 
-function _git-tag {
-  if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-    test -n "${VCS_STATUS_TAG}" && echo "${VCS_STATUS_TAG}"
-  else
-    git describe --tags --exact-match 2> /dev/null
-  fi
+function _git-tag() {
+	if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+		if [[ -n "${VCS_STATUS_TAG:-}" ]]; then
+			echo "${VCS_STATUS_TAG}"
+		fi
+	else
+		git describe --tags --exact-match 2> /dev/null
+	fi
 }
 
-function _git-commit-description {
-  git describe --contains --all 2> /dev/null
+function _git-commit-description() {
+	git describe --contains --all 2> /dev/null
 }
 
-function _git-short-sha {
-  if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-    echo ${VCS_STATUS_COMMIT:0:7}
-  else
-    git rev-parse --short HEAD
-  fi
+function _git-short-sha() {
+	if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+		echo "${VCS_STATUS_COMMIT:0:7}"
+	else
+		git rev-parse --short HEAD
+	fi
 }
 
 # Try the checked-out branch first to avoid collision with branches pointing to the same ref.
-function _git-friendly-ref {
-  if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-    _git-branch || _git-tag || _git-short-sha # there is no tag based describe output in gitstatus
-  else
-    _git-branch || _git-tag || _git-commit-description || _git-short-sha
-  fi
+function _git-friendly-ref() {
+	if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+		_git-branch || _git-tag || _git-short-sha # there is no tag based describe output in gitstatus
+	else
+		_git-branch || _git-tag || _git-commit-description || _git-short-sha
+	fi
 }
 
-function _git-num-remotes {
-  git remote | wc -l
+function _git-num-remotes() {
+	git remote | wc -l
 }
 
-function _git-upstream {
-  local ref
-  ref="$(_git-symbolic-ref)" || return 1
-  git for-each-ref --format="%(upstream:short)" "${ref}"
+function _git-upstream() {
+	local ref
+	ref="$(_git-symbolic-ref)" || return 1
+	git for-each-ref --format="%(upstream:short)" "${ref}"
 }
 
-function _git-upstream-remote {
-  local upstream
-  upstream="$(_git-upstream)" || return 1
+function _git-upstream-remote() {
+	local upstream branch
+	upstream="$(_git-upstream)" || return 1
 
-  local branch
-  branch="$(_git-upstream-branch)" || return 1
-  echo "${upstream%"/${branch}"}"
+	branch="$(_git-upstream-branch)" || return 1
+	echo "${upstream%"/${branch}"}"
 }
 
-function _git-upstream-branch {
-  local ref
-  ref="$(_git-symbolic-ref)" || return 1
+function _git-upstream-branch() {
+	local ref
+	ref="$(_git-symbolic-ref)" || return 1
 
-  # git versions < 2.13.0 do not support "strip" for upstream format
-  # regex replacement gives the wrong result for any remotes with slashes in the name,
-  # so only use when the strip format fails.
-  git for-each-ref --format="%(upstream:strip=3)" "${ref}" 2> /dev/null || git for-each-ref --format="%(upstream)" "${ref}" | sed -e "s/.*\/.*\/.*\///"
+	# git versions < 2.13.0 do not support "strip" for upstream format
+	# regex replacement gives the wrong result for any remotes with slashes in the name,
+	# so only use when the strip format fails.
+	git for-each-ref --format="%(upstream:strip=3)" "${ref}" 2> /dev/null || git for-each-ref --format="%(upstream)" "${ref}" | sed -e "s/.*\/.*\/.*\///"
 }
 
-function _git-upstream-behind-ahead {
-  git rev-list --left-right --count "$(_git-upstream)...HEAD" 2> /dev/null
+function _git-upstream-behind-ahead() {
+	git rev-list --left-right --count "$(_git-upstream)...HEAD" 2> /dev/null
 }
 
-function _git-upstream-branch-gone {
-  [[ "$(git status -s -b | sed -e 's/.* //')" == "[gone]" ]]
+function _git-upstream-branch-gone() {
+	[[ "$(git status -s -b | sed -e 's/.* //')" == "[gone]" ]]
 }
 
-function _git-hide-status {
-  [[ "$(git config --get bash-it.hide-status)" == "1" ]]
+function _git-hide-status() {
+	[[ "$(git config --get bash-it.hide-status)" == "1" ]]
 }
 
-function _git-status {
-  local git_status_flags=
-  [[ "${SCM_GIT_IGNORE_UNTRACKED}" = "true" ]] && git_status_flags='-uno' || true
-  git status --porcelain ${git_status_flags} 2> /dev/null
+function _git-status() {
+	local git_status_flags=
+	if [[ "${SCM_GIT_IGNORE_UNTRACKED:-}" == "true" ]]; then
+		git_status_flags='-uno'
+	fi
+	git status --porcelain "${git_status_flags:---}" 2> /dev/null
 }
 
-function _git-status-counts {
-  _git-status | awk '
+function _git-status-counts() {
+	_git-status | awk '
   BEGIN {
     untracked=0;
     unstaged=0;
@@ -116,85 +123,51 @@ function _git-status-counts {
   }'
 }
 
-function _git-remote-info {
+function _git-remote-info() {
+	local same_branch_name="" branch_prefix
+	# prompt handling only, reimplement because patching the routine below gets ugly
+	if [[ "${SCM_GIT_GITSTATUS_RAN:-}" == "true" ]]; then
+		[[ "${VCS_STATUS_REMOTE_NAME?}" == "" ]] && return
+		[[ "${VCS_STATUS_LOCAL_BRANCH?}" == "${VCS_STATUS_REMOTE_BRANCH?}" ]] && same_branch_name=true
+		# no multiple remote support in gitstatusd
+		if [[ "${SCM_GIT_SHOW_REMOTE_INFO:-}" == "true" || "${SCM_GIT_SHOW_REMOTE_INFO:-}" == "auto" ]]; then
+			if [[ ${same_branch_name:-} != "true" ]]; then
+				remote_info="${VCS_STATUS_REMOTE_NAME?}/${VCS_STATUS_REMOTE_BRANCH?}"
+			else
+				remote_info="${VCS_STATUS_REMOTE_NAME?}"
+			fi
+		elif [[ ${same_branch_name:-} != "true" ]]; then
+			remote_info="${VCS_STATUS_REMOTE_BRANCH?}"
+		fi
+		if [[ -n "${remote_info:-}" ]]; then
+			# no support for gone remote branches in gitstatusd
+			branch_prefix="${SCM_THEME_BRANCH_TRACK_PREFIX:-}"
+			echo "${branch_prefix}${remote_info:-}"
+		fi
+	else
+		[[ "$(_git-upstream)" == "" ]] && return
 
-  # prompt handling only, reimplement because patching the routine below gets ugly
-  if [[ "${SCM_GIT_GITSTATUS_RAN}" == "true" ]]; then
-    [[ "${VCS_STATUS_REMOTE_NAME}" == "" ]] && return
-    [[ "${VCS_STATUS_LOCAL_BRANCH}" == "${VCS_STATUS_REMOTE_BRANCH}" ]] && local same_branch_name=true
-    local same_branch_name=
-    [[ "${VCS_STATUS_LOCAL_BRANCH}" == "${VCS_STATUS_REMOTE_BRANCH}" ]] && same_branch_name=true
-    # no multiple remote support in gitstatusd
-    if [[ "${SCM_GIT_SHOW_REMOTE_INFO}" = "true" || "${SCM_GIT_SHOW_REMOTE_INFO}" = "auto" ]]; then
-      if [[ "${same_branch_name}" != "true" ]]; then
-        remote_info="${VCS_STATUS_REMOTE_NAME}/${VCS_STATUS_REMOTE_BRANCH}"
-      else
-        remote_info="${VCS_STATUS_REMOTE_NAME}"
-      fi
-    elif [[ ${same_branch_name} != "true" ]]; then
-      remote_info="${VCS_STATUS_REMOTE_BRANCH}"
-    fi
-    if [[ -n "${remote_info:-}" ]];then
-      # no support for gone remote branches in gitstatusd
-      local branch_prefix="${SCM_THEME_BRANCH_TRACK_PREFIX}"
-      echo "${branch_prefix}${remote_info}"
-    fi
-  else
-    [[ "$(_git-upstream)" == "" ]] && return
-
-    [[ "$(_git-branch)" == "$(_git-upstream-branch)" ]] && local same_branch_name=true
-    local same_branch_name=
-    [[ "$(_git-branch)" == "$(_git-upstream-branch)" ]] && same_branch_name=true
-    if [[ ("${SCM_GIT_SHOW_REMOTE_INFO}" = "auto" && "$(_git-num-remotes)" -ge 2) ||
-           "${SCM_GIT_SHOW_REMOTE_INFO}" = "true" ]]; then
-      if [[ "${same_branch_name}" != "true" ]]; then
-        remote_info="\$(_git-upstream)"
-      else
-        remote_info="$(_git-upstream-remote)"
-      fi
-    elif [[ ${same_branch_name} != "true" ]]; then
-      remote_info="\$(_git-upstream-branch)"
-    fi
-    if [[ -n "${remote_info:-}" ]];then
-      local branch_prefix
-      if _git-upstream-branch-gone; then
-        branch_prefix="${SCM_THEME_BRANCH_GONE_PREFIX}"
-      else
-        branch_prefix="${SCM_THEME_BRANCH_TRACK_PREFIX}"
-      fi
-      echo "${branch_prefix}${remote_info}"
-    fi
-  fi
-}
-
-# Unused by bash-it, present for API compatibility
-function git_status_summary {
-  awk '
-  BEGIN {
-    untracked=0;
-    unstaged=0;
-    staged=0;
-  }
-  {
-    if (!after_first && $0 ~ /^##.+/) {
-      print $0
-      seen_header = 1
-    } else if ($0 ~ /^\?\? .+/) {
-      untracked += 1
-    } else {
-      if ($0 ~ /^.[^ ] .+/) {
-        unstaged += 1
-      }
-      if ($0 ~ /^[^ ]. .+/) {
-        staged += 1
-      }
-    }
-    after_first = 1
-  }
-  END {
-    if (!seen_header) {
-      print
-    }
-    print untracked "\t" unstaged "\t" staged
-  }'
+		[[ "$(_git-branch)" == "$(_git-upstream-branch)" ]] && same_branch_name=true
+		if [[ ("${SCM_GIT_SHOW_REMOTE_INFO}" == "auto" && "$(_git-num-remotes)" -ge 2) ||
+		"${SCM_GIT_SHOW_REMOTE_INFO}" == "true" ]]; then
+			if [[ ${same_branch_name:-} != "true" ]]; then
+				# shellcheck disable=SC2016
+				remote_info='$(_git-upstream)'
+			else
+				remote_info="$(_git-upstream-remote)"
+			fi
+		elif [[ ${same_branch_name:-} != "true" ]]; then
+			# shellcheck disable=SC2016
+			remote_info='$(_git-upstream-branch)'
+		fi
+		if [[ -n "${remote_info:-}" ]]; then
+			local branch_prefix
+			if _git-upstream-branch-gone; then
+				branch_prefix="${SCM_THEME_BRANCH_GONE_PREFIX:-}"
+			else
+				branch_prefix="${SCM_THEME_BRANCH_TRACK_PREFIX:-}"
+			fi
+			echo "${branch_prefix}${remote_info:-}"
+		fi
+	fi
 }
diff --git a/themes/p4helpers.theme.bash b/themes/p4helpers.theme.bash
index 27a777ac..30b520cc 100644
--- a/themes/p4helpers.theme.bash
+++ b/themes/p4helpers.theme.bash
@@ -1,18 +1,18 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
 
 function _p4-opened {
-  timeout 2.0s p4 opened -s 2> /dev/null
+	timeout 2.0s p4 opened -s 2> /dev/null
 }
 
 function _p4-opened-counts {
-  # Return the following counts seperated by tabs:
-  #  - count of opened files
-  #  - count of pending changesets (other than defaults)
-  #  - count of files in the default changeset
-  #  - count of opened files in add mode
-  #  - count of opened files in edit mode
-  #  - count of opened files in delete mode
-  _p4-opened | awk '
+	# Return the following counts seperated by tabs:
+	#  - count of opened files
+	#  - count of pending changesets (other than defaults)
+	#  - count of files in the default changeset
+	#  - count of opened files in add mode
+	#  - count of opened files in edit mode
+	#  - count of opened files in delete mode
+	_p4-opened | awk '
   BEGIN {
     opened=0;
     type_array["edit"]=0;