diff --git a/travis_build.script b/travis_build.script
index a49a44a..20a2fd1 100755
--- a/travis_build.script
+++ b/travis_build.script
@@ -1,4 +1,5 @@
 #! /bin/bash
+set -e
 # Travis runs Ubuntu 12.04 and misses libutfcpp-dev.
 cp source/misc/travis_help/utf8_v2_3_4/source/utf8.h source/code/
 cp -r source/misc/travis_help/utf8_v2_3_4/source/utf8 source/code/