What language is that?

Well I found a nice tutorial about how to program applications using开发者_C百科 Bonjour. It's cool. But the only problem, I do not understand which language they teach. I am not even sure that it is a programming language? May be they write about commands that should be typed in a command line? Or may be these are commands which should be executed in some GUI applications? Somehow I cannot find the context in which this tutorial is given. It is strange to me that they do not write what is that.

Can somebody resolve this mystery?

Its the C API for apple's Bonjour services; this is hardly a programming tutorial.

Looking at the left, there's a block that says:

RELATED REFERENCE 
PROCEDURAL C DNS
Service Discovery C Reference

I'm going to go out on a limb and say it's probably C.

From the URL, title, and menu you can tell that it's a article about registering services using their dns_discovery_api in C.

This is not a programming tutorial.

That’s not a tutorial about how to program, OS X programs are written in Objective-C (although this is a C API), and that page has a table of contents on the left side.

The mDNS command line tool can be used to test Bonjour services.