diff --git a/maxscale-system-test/mdbci/set_env.sh b/maxscale-system-test/mdbci/set_env.sh
index 732d15ba9..bc113dc23 100644
--- a/maxscale-system-test/mdbci/set_env.sh
+++ b/maxscale-system-test/mdbci/set_env.sh
@@ -1,8 +1,10 @@
+#!/bin/bash
 set -x
 echo $*
 export MDBCI_VM_PATH=${MDBCI_VM_PATH:-$HOME/vms}
 export mdbci_dir=${mdbci_dir:-"$HOME/mdbci/"}
-export script_dir="$(dirname $(readlink -f $0))"
+export script_dir="$(dirname `readlink -f -- $0`)"
+
 
 export config_name="$1"
 if [ -z $1 ] ; then