Augeas is a configuration editing tool. It parses configuration files in their native formats and transforms them into a tree. Configuration changes are made by manipulating this tree and saving it back into native config files.

The tool, and this description, recently turned 10 years old, a milestone that I will celebrate with a stroll down memory lane, looking at Augeas' original goals and subsequent achievements over the past decade. Over that time, it has become an important building block for configuration management tools like Puppet and Salt, and is used by tools such as EFF's Let's Encrypt, OSQuery, and libvirt.

I will talk about some of the basic patterns for using Augeas to perform surgery on configuration files, share some tips on how to get the most out of its tree structure, and how to use it to perform idempotent changes. I will also talk about a few areas where Augeas can be improved, and where it's use could be simplified.