diff --git a/t/t7408-submodule-reference.sh b/t/t7408-submodule-reference.sh
index b770b2f04d..eaea19b8f2 100755
--- a/t/t7408-submodule-reference.sh
+++ b/t/t7408-submodule-reference.sh
@@ -6,7 +6,7 @@
 test_description='test clone --reference'
 . ./test-lib.sh
 
-base_dir=`pwd`
+base_dir=$(pwd)
 
 U=$base_dir/UPLOAD_LOG