diff --git a/linebreak.sh b/linebreak.sh
index cadada3..ac395e4 100755
--- a/linebreak.sh
+++ b/linebreak.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 
 # Copyright (C) 2010 Swiss Library for the Blind, Visually Impaired and Print Disabled
 #