What does this language look like? It's not a series of instructions, such as a shell script or a Ruby program. It's more like a set of declarations about the way things should be:

package { 'curl':
  ensure => installed,
}

In English, this code says, "The curl package should be installed". This snippet of code results in Puppet doing the following:

Another example is as follows:

user { 'jen':
  ensure => present,
}

This is Puppet language for the declaration "The jen user should be present." Again, this results in Puppet checking for the existence of the jen user on the system, and creating it if necessary.

So you can see that the Puppet program—the Puppet manifest—for your configuration is a set of declarations about what things should exist, and how they should be configured.

You don't give commands, such as "Do this, then do that." Rather, you describe how things should be, and let Puppet take care of making it happen. These are two quite different kinds of programming. The first (procedural style) is the traditional model used by languages, such as C, Python, shell, and so on. Puppet's is called declarative style because you declare what the end result should be, rather than specifying the steps to get there.

This means that you can apply the same Puppet manifest repeatedly to a machine and the end result will be the same, no matter how many times you run the "program". It's better to think of Puppet manifests as a kind of executable specification rather than as a program in the traditional sense.

This is powerful because the same manifest—"The curl package should be installed and the jen user should be present"—can be applied to different machines all running different operating systems.

Puppet lets you describe configuration in terms of resources—what things should exist—and their attributes. You don't have to get into the details of how resources are created and configured on different platforms. Puppet just takes care of it.

Here are some of the kinds of resources you can describe in Puppet:

In fact, since you can define custom resources to manage anything that's not covered by the built-in resources, there are no limits. Puppet allows you to automate every possible aspect of system configuration.