Every Unix/Linux user has typed sudo countless times, but have you ever wondered what happens behind the scenes when this seemingly simple command grants you temporary root privileges? The sudo (superuser do) command is one of the most important yet underappreciated tools in Unix systems, handling the delicate balance between user convenience and system security.

In this post, we’ll peel back the layers to understand how sudo works—from user authentication and permission checking to process execution with elevated privileges. We’ll also implement a basic sudo-like system from scratch to truly understand the Unix mechanisms that make privilege escalation possible.