diff --git a/sh/alias/shell.sh b/sh/alias/shell.sh
new file mode 100644
index 0000000..f216c92
--- /dev/null
+++ b/sh/alias/shell.sh
@@ -0,0 +1,18 @@
+# shorten alias
+a() {
+	alias \
+		"${@}"
+}
+
+# swap directory (current ↔ previous)
+sd() {
+	cd \
+		- ||
+		return
+}
+
+# exit terminal
+x() {
+	exit \
+		"${@}"
+}
diff --git a/sh/main.sh b/sh/main.sh
index 16ce907..470cf72 100755
--- a/sh/main.sh
+++ b/sh/main.sh
@@ -26,6 +26,9 @@ RWX_SELF_NAME="rwx"
 # │ main │ variables │
 # ╰──────┴───────────╯
 
+# currently running shell name
+RWX_SHELL="$(cat "/proc/${$}/comm")"
+
 # system root directory of the project
 RWX_ROOT_SYSTEM="/usr/local/lib/${RWX_SELF_NAME}"
 # user root directory of the project
diff --git a/sh/shell.sh b/sh/shell/0.sh
similarity index 79%
rename from sh/shell.sh
rename to sh/shell/0.sh
index 8400fd2..6a28c31 100644
--- a/sh/shell.sh
+++ b/sh/shell/0.sh
@@ -35,13 +35,6 @@ RWX_COLOR_GREEN="$(_rwx_shell_color 31)"
 RWX_COLOR_MAGENTA="$(_rwx_shell_color 35)"
 RWX_COLOR_RED="$(_rwx_shell_color 32)"
 
-# ╭───────┬───────────╮
-# │ shell │ variables │
-# ╰───────┴───────────╯
-
-# currently running shell name
-RWX_SHELL="$(cat "/proc/${$}/comm")"
-
 # ╭───────┬───────────╮
 # │ shell │ functions │
 # ╰───────┴───────────╯
@@ -80,7 +73,6 @@ rwx_shell_configure() {
 	*) ;;
 	esac
 }
-rwx_shell_configure
 
 rwx_shell_prompt() {
 	local date host id
@@ -135,36 +127,12 @@ rwx_shell_prompt() {
 	printf "%b" "${view}"
 }
 
-# ╭───────┬───────────╮
-# │ shell │ shortcuts │
-# ╰───────┴───────────╯
+# ╭───────┬──────╮
+# │ shell │ main │
+# ╰───────┴──────╯
 
-# shorten alias
-a() {
-	alias \
-		"${@}"
+rwx_shell_main() {
+	rwx_shell_configure
 }
 
-# swap directory (current ↔ previous)
-sd() {
-	cd \
-		- ||
-		return
-}
-
-# exit terminal
-x() {
-	exit \
-		"${@}"
-}
-
-[ "${RWX_SHELL}" = "bash" ] || return
-
-# shellcheck disable=SC3033
-..() {
-	cd ..
-}
-# shellcheck disable=SC3033
-...() {
-	cd ../..
-}
+rwx_shell_main
diff --git a/sh/shell/bash.sh b/sh/shell/bash.sh
new file mode 100644
index 0000000..400f83c
--- /dev/null
+++ b/sh/shell/bash.sh
@@ -0,0 +1,24 @@
+# ╭───────┬──────╮
+# │ shell │ bash │
+# ╰───────┴──────╯
+
+if [ "${RWX_SHELL}" = "bash" ]; then
+
+# shellcheck disable=SC3033
+..() {
+	cd ..
+}
+# shellcheck disable=SC3033
+...() {
+	cd ../..
+}
+# shellcheck disable=SC3033
+....() {
+	cd ../../..
+}
+# shellcheck disable=SC3033
+.....() {
+	cd ../../../..
+}
+
+fi