Use more restrictive shell options

deploy.sh

@@ -1,12 +1,16 @@
 #!/bin/sh
 
+set -eu
+
 # run sudo to cache creds
 sudo /bin/true
 
 # update modules and check depencies
 git pull
 git submodule update --init --recursive
-rpm -q ansible > /dev/null || sudo yum -y install ansible
+if ! rpm -q ansible > /dev/null; then
+    sudo yum -y install ansible
+fi
 
 # run playbook
 ansible-playbook deploy.yml