I am a C++ beginner.

I'd like to create small programs that interact with the operating system (using Kubuntu Linux). So far, I have not been able to locate any tutorial or handbook to get C++ to interface with the OS.

In PHP, I can use the command exec() or the backtick operator to launch commands typically executed in a console.
How can I do similar things in C++?
How can I get my C++ program to execute any other command?
How can I get the output of such commands?

Thanks.