diff --git a/travis-linux b/travis-linux
index 47f1940..2b768db 100755
--- a/travis-linux
+++ b/travis-linux
@@ -2,6 +2,6 @@
 set -euo pipefail
 
 sudo apt-get install software-properties-common
-sudo add-apt-repository ppa:george-edison55/cmake-3.x
+sudo add-apt-repository --yes ppa:george-edison55/cmake-3.x
 sudo apt-get update
 PREBUILT=1 ./make-linux