With the release of Puppet 2.6, a brand new concept was introduced: Puppet faces.
Faces are an API that allow easy creation of new Puppet (sub) commands: whenever we execute Puppet, we specify at least one command, which provides access to the functionalities of its subsystems.
The most common commands are
cert and have existed for a long time but there are a lot more (we can see their full list with
puppet help) and most of them are defined via the faces API.
As you can guess, we can easily add new faces and therefore, new subcommands to the Puppet executable just by placing some files in a module of ours.
The typical synopsis of a face reflects the Puppet command's one:
puppet [FACE] [ACTION] [ARGUMENTS] [OPTIONS] ...