Linux Terminal Playground

What is this?

A Linux shell that runs entirely in your browser. It emulates a small server — with a home directory, logs, nginx and SSH configuration — in two flavours: Ubuntu 24.04 (Debian family) and Rocky Linux 9 (RHEL-compatible: RHEL, Rocky, AlmaLinux). Switch between them to see where they differ: /var/log/auth.log vs /var/log/secure, sudo vs wheel, sites-available vs conf.d. You can practice commands without a VM, a cloud account, or the fear of breaking something. Nothing is sent to a server, and Reset brings the machine back to its starting state.

What you can do

• Navigate and manage files: ls -la, cd, tree, mkdir -p, cp -r, mv, rm -r
• Read and search: cat, head, tail, grep -rn, find, wc
• Combine commands with pipes and redirections: grep error app.log | sort | uniq -c > summary.txt
• Work with permissions: chmod 640, chmod u+x, sudo, sudo -i
• Check disk usage: du -sh, df -h, find / -size +500M

Type help inside the terminal for the full list, and man <command> for the options each one supports.

Scenarios

Many OhSudo articles come with a scenario: the terminal opens with files and a problem prepared for that article, so you can follow along step by step. Look for the “Practice this in the terminal” box at the end of an article.

FAQ

Is it safe to try rm -rf here?

Yes. Everything happens in a pretend filesystem in your browser tab. Try sudo rm -rf /var/log and see what happens — then hit Reset. (It’s still a terrible idea on a real server.)

Why do some commands say “Permission denied”?

Just like on a real server, you’re logged in as a normal user, guest. Files like /etc/shadow or /var/log/auth.log need root: put sudo in front of the command, or run sudo -i to get a root shell (exit to leave it).

Will my files still be there tomorrow?

Not yet — the machine starts fresh every time you open the page. Saving your progress is planned.