diff --git a/shell/alias/shell.sh b/shell/alias/shell.sh
index d38c3cb..531b4b0 100644
--- a/shell/alias/shell.sh
+++ b/shell/alias/shell.sh
@@ -17,6 +17,9 @@ x() {
 		"${@}"
 }
 
+# shellcheck disable=SC2154
+[ "${SH}" = "bash" ] || return
+
 # back
 
 # shellcheck disable=SC3033
diff --git a/shell/main.sh b/shell/main.sh
index 0ccf86b..226062c 100644
--- a/shell/main.sh
+++ b/shell/main.sh
@@ -1,5 +1,8 @@
 [ -n "${ENV}" ] || export ENV="/etc/shell/main.sh"
 
+SH="$(cat /proc/$$/comm)"
+export SH
+
 main_source_directory() {
 	local path="${1}"
 	if [ -d "${path}" ]; then
diff --git a/shell/shell.sh b/shell/shell.sh
index b50964e..edddde6 100644
--- a/shell/shell.sh
+++ b/shell/shell.sh
@@ -1,10 +1,10 @@
 PS1="\$(shell_prompt \${?})"
 PS2="\
 ├ "
-SH="$(cat /proc/$$/comm)"
 
 shell_color() {
 	local code="${1}"
+	# shellcheck disable=SC2154
 	case "${SH}" in
 	"bash")
 		printf "\e[0"