After you understand pointers and structs and have futzed around in the Unix command line for a while, you probably have enough to go on to something like Linux Programming by Example. This book walks through GNU implementations of Unix utilities and the system calls that make them possible.
You don't just want to run ls, you want to know enough that you can write ls by yourself. You want to learn how to manipulate the operating system with it. You will learn a mental model for how operating systems work in a deep, detailed way, which will serve you well no matter where you go.
After you understand pointers and structs and have futzed around in the Unix command line for a while, you probably have enough to go on to something like Linux Programming by Example. This book walks through GNU implementations of Unix utilities and the system calls that make them possible.
You don't just want to run ls, you want to know enough that you can write ls by yourself. You want to learn how to manipulate the operating system with it. You will learn a mental model for how operating systems work in a deep, detailed way, which will serve you well no matter where you go.