diff --git a/.config/bash/module/Tmux.sh b/.config/bash/module/Tmux.sh
index 9b5f2de..5060fbe 100644
--- a/.config/bash/module/Tmux.sh
+++ b/.config/bash/module/Tmux.sh
@@ -11,7 +11,7 @@ function ta() {
 	tmux new-session -s "${name}" -d &> /dev/null
 
 	# Attach to session.
-	if [[ "${TERM_PROGRAM}" = "tmux" ]]; then
+	if _is_tmux; then
 		tmux switch-client -t "${name}"
 	else
 		tmux attach-session -t "${name}"
diff --git a/.config/bash/module/Util.sh b/.config/bash/module/Util.sh
index 79bfa7b..4910879 100644
--- a/.config/bash/module/Util.sh
+++ b/.config/bash/module/Util.sh
@@ -116,3 +116,8 @@ function _contains() {
 
 	return 1
 }
+
+# Check if inside Tmux.
+function _is_tmux() {
+	[[ "${TERM_PROGRAM}" = "tmux" ]]
+}