diff --git a/sh/code.awk b/sh/core/code.awk
similarity index 100%
rename from sh/code.awk
rename to sh/core/code.awk
diff --git a/sh/code.sh b/sh/core/code.sh
similarity index 91%
rename from sh/code.sh
rename to sh/core/code.sh
index 5a67869..a4a5eb0 100644
--- a/sh/code.sh
+++ b/sh/core/code.sh
@@ -8,12 +8,12 @@
 
 # TODO variablize
 # path to the entrypoint main file of the project
-RWX_MAIN_PATH="${RWX_ROOT_SYSTEM}/${RWX_MAIN_NAME}"
+RWX_MAIN_PATH="${RWX_ROOT_SYSTEM}/${RWX_MAIN_NAME}.${RWX_MAIN_EXTENSION}"
 # user root directory of the project
 RWX_SELF_USER="${HOME}/${RWX_SELF_NAME}"
 
 # cache for the parsing awk script
-_rwx_code_awk="$(cat "${RWX_ROOT_SYSTEM}/code.awk")"
+_rwx_code_awk="$(cat "${RWX_ROOT_SYSTEM}/core/code.awk")"
 # cache for code aliases
 _rwx_code_aliases=""
 # cache for code aliases functions
@@ -37,7 +37,7 @@ _rwx_code_variables=""
 
 # output help message
 rwx_code_help() {
-	rwx_log \
+	rwx_log "" \
 		"rwx_… = functions" \
 		" a__… = aliases" \
 		" u__… = user"
@@ -59,7 +59,7 @@ rwx_code_install() {
 	fi
 	# commands
 	root="${target}/usr/local/bin"
-	name="${RWX_SELF_NAME}.sh"
+	name="${RWX_SELF_NAME}.${RWX_MAIN_EXTENSION}"
 	file="${root}/${name}"
 	rwx_remove "${file}"
 	rwx_link "${file}" "${RWX_MAIN_PATH}"
@@ -71,7 +71,7 @@ rwx_code_install() {
 ${_rwx_code_commands}
 EOF
 	# sh
-	file="${target}/etc/profile.d/${RWX_SELF_NAME}.sh"
+	file="${target}/etc/profile.d/${RWX_SELF_NAME}.${RWX_MAIN_EXTENSION}"
 	rwx_remove "${file}"
 	rwx_file_write "${file}" "\
 export ENV=\"${RWX_MAIN_PATH}\"
@@ -109,8 +109,8 @@ rwx_code_command_function() {
 	[ -n "${name}" ] || return
 	rwx_code |
 		awk \
-			--assign action="command function" \
-			--assign target="${name}" \
+			-v action="command function" \
+			-v target="${name}" \
 			"${_rwx_code_awk}"
 }
 
@@ -175,13 +175,13 @@ rwx_code_doc() {
 	[ -n "${name}" ] || return
 	rwx_code |
 		awk \
-			--assign action="doc" \
-			--assign target="${name}" \
+			-v action="doc" \
+			-v target="${name}" \
 			"${_rwx_code_awk}"
 }
 
 rwx_code_load() {
-	local line text
+	local line
 	# parse aliases functions
 	_rwx_code_aliases_functions="$(rwx_code_parse "aliases functions")"
 	while IFS= read -r line; do
@@ -214,7 +214,7 @@ rwx_code_parse() {
 	local action="${1}"
 	rwx_code |
 		awk \
-			--assign action="${action}" \
+			-v action="${action}" \
 			"${_rwx_code_awk}"
 }
 
@@ -246,11 +246,7 @@ rwx_code_main() {
 		fi
 	# context / shell
 	else
-		# run interactive extras
-		if rwx_shell_interactive; then
-			# help
-			rwx_log
-			rwx_code_help
-		fi
+		# display help
+		rwx_code_help
 	fi
 }
diff --git a/sh/lint/shellcheck.sh b/sh/lint/shellcheck.sh
index 0253062..75101f2 100644
--- a/sh/lint/shellcheck.sh
+++ b/sh/lint/shellcheck.sh
@@ -2,9 +2,9 @@ rwx_shellcheck() {
 	local root="${1}"
 	local file module modules path
 	file="$(mktemp)"
-	modules="$(rwx_find_shell "${root}")"
+	modules="$(rwx_main_find "${root}")"
 	while IFS= read -r module; do
-		path="${root}/${module}"
+		path="${root}/${module}.${RWX_MAIN_EXTENSION}"
 		echo ". \"${path}\"" >>"${file}"
 	done <<EOF
 ${modules}
diff --git a/sh/main.sh b/sh/main.sh
index f89ee47..401fccd 100755
--- a/sh/main.sh
+++ b/sh/main.sh
@@ -8,8 +8,11 @@
 # │ main │ constants │
 # ╰──────┴───────────╯
 
-# name of the entrypoint file
-RWX_MAIN_NAME="main.sh"
+# extension of shell modules
+RWX_MAIN_EXTENSION="sh"
+
+# name of the entrypoint module
+RWX_MAIN_NAME="main"
 # name of the project itself
 RWX_SELF_NAME="rwx"
 
@@ -28,37 +31,27 @@ RWX_ROOT_SYSTEM="/usr/local/lib/${RWX_SELF_NAME}"
 # │ main │ find │
 # ╰──────┴──────╯
 
-# find directory’s files by extension
+# find directory’s shell files
 #| find
+#| sed
 #| sort
-rwx_find_extension() {
-	local extension="${1}"
-	local root="${2}"
-	local file="${3}"
-	set -- \
+rwx_main_find() {
+	local root="${1}"
+	find \
 		"${root}" \
-		-name "*.${extension}" \
-		-type "f"
-	[ -n "${file}" ] &&
-		set -- "${@}" \
-			-not \
-			-name "${file}"
-	find "${@}" \
+		-name "*.${RWX_MAIN_EXTENSION}" \
+		-type "f" \
 		-printf "%P\n" |
+		sed "s|\\.[^.]*\$||" |
 		sort
 }
 
-# find directory’s sh files
-rwx_find_shell() {
-	rwx_find_extension "sh" "${@}"
-}
-
 # ╭──────┬───────╮
 # │ main │ shell │
 # ╰──────┴───────╯
 
 # test if active shell is in interactive mode
-rwx_shell_interactive() {
+rwx_main_interactive() {
 	case "${-}" in
 	*i*) ;;
 	*) return 1 ;;
@@ -70,7 +63,7 @@ rwx_shell_interactive() {
 # ╰──────┴─────╯
 
 _rwx_main_log() {
-	if rwx_shell_interactive; then
+	if rwx_main_interactive; then
 		[ ${#} -gt 0 ] || set -- ""
 		local line
 		for line in "${@}"; do
@@ -83,24 +76,25 @@ _rwx_main_log() {
 # │ main │ source │
 # ╰──────┴────────╯
 
-# source code from root path but file
+# source code from root path
 rwx_main_source() {
 	local root="${1}"
 	[ -d "${root}" ] ||
 		return 1
-	local file="${2}"
 	local count module modules
 	count=0
 	_rwx_main_log "" \
 		". ${root}"
-	modules="$(rwx_find_shell "${root}" "${file}")"
+	modules="$(rwx_main_find "${root}")"
 	while IFS= read -r module; do
-		count=$((count + 1))
-		_rwx_main_log "$(printf "%02d" "${count}") ${module%.sh}"
-		# shellcheck disable=SC1090
-		. "${root}/${module}"
-		# cache code
-		rwx_main_cache "${root}" "${module}"
+		if [ "${module}" != "${RWX_MAIN_NAME}" ]; then
+			count=$((count + 1))
+			_rwx_main_log "$(printf "%02d" "${count}") ${module}"
+			# shellcheck disable=SC1090
+			. "${root}/${module}.${RWX_MAIN_EXTENSION}"
+			# cache code
+			rwx_main_cache "${root}" "${module}"
+		fi
 	done <<EOF
 ${modules}
 EOF
@@ -116,13 +110,12 @@ EOF
 rwx_main_cache() {
 	local root="${1}"
 	local module="${2}"
-	local name="${module%.sh}"
-	local path="${root}/${module}"
+	local path="${root}/${module}.${RWX_MAIN_EXTENSION}"
 	local text
 	text="$(cat "${path}")"
 	# all source code
 	_rwx_code="${_rwx_code}\
-#. ${name}
+#. ${module}
 ${text}
 "
 }
@@ -132,12 +125,12 @@ ${text}
 # ╰──────┴──────╯
 
 # run initial steps
-#< code
+#< core/code
 rwx_main_main() {
 	# cache main
 	rwx_main_cache "${RWX_ROOT_SYSTEM}" "${RWX_MAIN_NAME}"
 	# source system root
-	if ! rwx_main_source "${RWX_ROOT_SYSTEM}" "${RWX_MAIN_NAME}"; then
+	if ! rwx_main_source "${RWX_ROOT_SYSTEM}"; then
 		_rwx_main_log "Not a directory: ${RWX_ROOT_SYSTEM}"
 		return 1
 	fi
diff --git a/sh/self.sh b/sh/self.sh
index 76424f3..fc62d88 100644
--- a/sh/self.sh
+++ b/sh/self.sh
@@ -11,11 +11,11 @@ rwx_self_subset() {
 	local argument file root
 	for argument in "${@}"; do
 		root="${RWX_ROOT_SYSTEM}/${argument}"
-		file="${argument}.sh"
+		file="${argument}.${RWX_MAIN_EXTENSION}"
 		if [ -d "${root}" ]; then
 			local file
-			for file in $(rwx_find_shell "${root}"); do
-				echo "${argument}/${file}"
+			for file in $(rwx_main_find "${root}"); do
+				echo "${argument}/${file}.${RWX_MAIN_EXTENSION}"
 			done
 		elif [ -f "${RWX_ROOT_SYSTEM}/${file}" ]; then
 			echo "${file}"