diff --git a/tools/git-submodule/install b/tools/git-submodule/install
index 602a5a4..aa38107 100755
--- a/tools/git-submodule/install
+++ b/tools/git-submodule/install
@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
+set -eu
+
 CONFIG="install.conf.json"
 DOTBOT_DIR="dotbot"