Oct 22, 2018

Linux as an operating system: the kernel and the user space

Linux as an operating system consists of two parts: the kernel and the user space. 

In a traditional operating system, the kernel runs on the hardware and you never interact with it directly. The user space is what you actually interact with and this includes all the files, libraries, and programs that you see when you look at a file browser or run the cat command.

When you use the nmcli command to change an IP address, you are actually leveraging a user space program to make kernel changes to the TCP stack.