diff --git a/sc2/subst b/sc2/subst
index aa6329475..16a5209cb 100755
--- a/sc2/subst
+++ b/sc2/subst
@@ -3,12 +3,9 @@
 
 # We need bash functionality. Executing bash with the shebang won't be
 # portable as the location of bash differs.
-SHELLFILE="$_"
-case "$SHELLFILE" in
-	sh|*/sh)
-		exec bash "$0" "$@"
-		;;
-esac
+if [ -z "$BASH_VERSION" ]; then
+	exec bash "$0" "$@"
+fi
 
 if [ $# -eq 0 ]; then
 	{