Hi All Ansible is a system configuration-management tool that is based on "playbooks". These are collections of mostly YAML files, but also Jinja2 templates and unix configuration files. To execute one needs to run a unix shell command with a python virtualenv set up and usually some environment variables set. Painfully much of this lives fragmented in a nested directory structure, many of the files in which are named "main.yml". Sometimes the same information has to be set in two places with incompatible formats , such as a config file and an environment variable. I am trying to bring some literate programming to bear on this can of worms so have reached for Babel. It's my first use of it. The current problem is that I have a config file that I want to substitute a value into. I want the conf-mode highlighting. Conf is not a programming language of course, just a text format. I'm trying something like #+begin_src conf :tangle yes :noweb yes [defaults] private_key_file = <> #+end_src I have tried something similar to the SQL comment example in the documentation to no avail and also setting :var headers. How can I substitute a value here? Cheers Steven