diff --git a/ensure-hashes.sh b/ensure-hashes.sh
index 4c126cd..61a7418 100644
--- a/ensure-hashes.sh
+++ b/ensure-hashes.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -eu
+
 TMPDIR=${1}
 
 cd ${TMPDIR} || exit 1