diff --git a/libexec/rbenv b/libexec/rbenv
index a9e0c8ec..ad5c97cb 100755
--- a/libexec/rbenv
+++ b/libexec/rbenv
@@ -59,7 +59,7 @@ export RBENV_ROOT
 if [ -z "${RBENV_DIR}" ]; then
   RBENV_DIR="$PWD"
 else
-  [[ $RBENV_DIR == /* ]] || RBENV_DIR=$PWD/$RBENV_DIR
+  [[ $RBENV_DIR == /* ]] || RBENV_DIR="$PWD/$RBENV_DIR"
   cd "$RBENV_DIR" 2>/dev/null || abort "cannot change working directory to \`$RBENV_DIR'"
   RBENV_DIR="$PWD"
   cd "$OLDPWD"