diff --git a/.travis.yml b/.travis.yml
index 2589aabb..e0a5b039 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -52,4 +52,4 @@ script:
   - make emulator-regression-tests -C regression SUITE=$SUITE TORTURE_CONFIG=default
 
 before_cache:
-  - ls -tr regression/install | tail -n+2 | sed s@^@regression/install/@ | xargs rm -rf
+  - ls -t regression/install | tail -n+2 | sed s@^@regression/install/@ | xargs rm -rf