The Phantom Process

ps and top X-ray the processes you can't see from outside, exposing the CPU hog at a glance

Your laptop suddenly slows to a crawl. The fan roars. You're not running anything heavy, just a browser and a text editor. So what's eating all your CPU and memory? Invisible processes. Every browser tab, every extension, every cloud sync service runs as its own process in the background.

This is exactly what ps aux and top are for. Run top and the invisible becomes visible: you can see exactly which process is hogging 80% of your CPU. The %CPU and %MEM columns (MEM in macOS top) tell you the culprit at a glance.

The terminal is like an X-ray for your computer. It shows you what's hidden beneath the surface.