Fundamentals

Start here if you're building a mental model of Linux from the ground up. These pages cover the concepts everything else on this site assumes you already have.

• Kernel vs. Distribution

  The kernel is shared across almost all Linux systems; a distribution is the specific bundle of kernel, package manager, init system, and defaults that turns it into something installable.

• The Boot Process

  From power-on to login prompt, a Linux machine moves through firmware, a bootloader, the kernel, and finally the init system - knowing the order matters most when something fails partway through.

• The Filesystem Hierarchy

  Linux presents all storage as a single tree rooted at /, with standardized directories for standardized purposes - the Filesystem Hierarchy Standard (FHS) defines what goes where.

• What Is Linux?

  Linux is a kernel, not an operating system by itself - what that distinction means in practice and why "Linux" ends up meaning different things depending on context.