Processes & Resources

Intermediate

Overview

A process is a running program identified by a PID. ps lists processes, and top (or htop) shows them live with CPU and memory usage.

Send signals to processes with kill. The default signal asks politely to stop (SIGTERM, 15); kill -9 forces termination (SIGKILL) and should be a last resort.

Append & to run a command in the background, and use jobs, fg, and bg to manage backgrounded work in your current shell.

Cheatsheet

ps auxList all processes with resource usage

ps aux | grep nginxFind a specific process

topLive view of processes (q to quit)

kill 1234Gracefully stop PID 1234

kill -9 1234Force kill PID 1234

command &Run a command in the background

Try it

A safe, simulated terminal. Run the suggested commands to see typical output.

simulated terminal

Type a command and press Enter, or click a suggestion below to run it.

Quick quiz

1. Which signal does `kill -9` send?

2. How do you run a command in the background?