diff --git a/gpMgmt/bin/generate-greenplum-path.sh b/gpMgmt/bin/generate-greenplum-path.sh
index 3fed2e3b8b915fd51330a9872a508cfce6f5eba6..6695c96632b428d6ec4362d01c253a04db428142 100755
--- a/gpMgmt/bin/generate-greenplum-path.sh
+++ b/gpMgmt/bin/generate-greenplum-path.sh
@@ -1,10 +1,10 @@
 #!/usr/bin/env bash
 
 cat <<"EOF"
-if test -n "$ZSH_VERSION"; then
+if test -n "${ZSH_VERSION:-}"; then
     # zsh
     SCRIPT_PATH="${(%):-%x}"
-elif test -n "$BASH_VERSION"; then
+elif test -n "${BASH_VERSION:-}"; then
     # bash
     SCRIPT_PATH="${BASH_SOURCE[0]}"
 else