diff --git a/scripts/partial_tempering.sh b/scripts/partial_tempering.sh
index d4ba669853604c516ee19998dd0b6c94fbb0181d..5555cd5c6d3e19547b608caffd67428e7d914825 100755
--- a/scripts/partial_tempering.sh
+++ b/scripts/partial_tempering.sh
@@ -1,3 +1,4 @@
+#! /bin/bash
 # vim:ft=awk
 if [ "$1" = --description ] ; then
   echo "create a new collective variable from a template"