Practice
Linux terminal
A practice Linux shell in your browser: real commands on a pretend machine, so nothing you type can break anything. Start in the playground or pick an exercise.
Enter runs a command. ↑ and ↓ recall earlier ones, Tab completes names, Ctrl+L clears, Ctrl+C cancels the line.
This is a simulated shell built for learning, not a full Linux system: the common commands for files, permissions and text work as they do on a real machine, but there are no real processes, no package installs and no network. For those, use a real Linux machine, such as AWS CloudShell in the course labs.