Other machines: ssh and package managers

ssh: your shell, on another computer

Every server you'll ever deploy to is a Linux machine in some datacenter, and you'll drive it with the exact skills from this course. ssh (secure shell) opens a shell on a remote machine over an encrypted connection:

ssh deploy@example.com

Read it as user@machine. After connecting, your prompt changes and every command you type (cd, ls, tail, all of it) runs over there, on that machine's filesystem. exit brings you home.

Instead of passwords, professionals use key pairs: a private key file that stays on your laptop (chmod 600!) and a public key placed on the server. ssh-keygen creates the pair. Bonus tool: scp file user@host:path copies files across, cp-style.

Installing software: package managers

On Linux you don't download installers from websites. A package manager fetches, installs, and updates software from a trusted catalog. On Debian/Ubuntu it's apt:

sudo apt update        # refresh the catalog
sudo apt install htop  # install a program

Two notes:

• sudo runs one command as the administrator (root). Installing system software needs it. With great power: sudo + rm -rf is the most dangerous combo in computing.
• Other systems, same idea: dnf (Fedora), pacman (Arch), brew (macOS), and language-specific ones you'll meet later like npm and pip.