diff --git a/sc2/subst b/sc2/subst
index d8615ba63..aa6329475 100755
--- a/sc2/subst
+++ b/sc2/subst
@@ -1,7 +1,15 @@
-#!/bin/bash
-#!/usr/bin/bash
+#!/bin/sh
 # Substitute a string in many files. By Serge van den Boom, 20020826
 
+# 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 [ $# -eq 0 ]; then
 	{
 		echo "subst: substitute a string in a lot of files."