diff --git a/make/scripts/fixpath.sh b/make/scripts/fixpath.sh
index 1a894df5413..35b796ca4e3 100644
--- a/make/scripts/fixpath.sh
+++ b/make/scripts/fixpath.sh
@@ -166,7 +166,7 @@ function import_path() {
           # unixpath is based on short name
         fi
         # Make it lower case
-        path="$(echo "$unixpath" | tr [:upper:] [:lower:])"
+        path="$(echo "$unixpath" | tr '[:upper:]' '[:lower:]')"
       fi
     else
       # On WSL1, PATHTOOL will fail for files in envroot. If the unix path