No programming today. We will look at the path from your code to a page that someone else can see, and set up all accounts and tools. Nothing moves forward without this step.

• client: the program that asks for a page, in our case the browser.
• server: the computer that sends the page. Our server is called sigma.
• HTTP: the protocol the client and the server use to talk. HTTPS is the same, but encrypted.
• URL: the address of a page, e.g. https://sigma.tuke.sk/student/name.surname/.
• static page: an HTML file the server sends as it is (HTML, CSS, JavaScript).
• dynamic page: the server builds it at the moment someone asks for it (PHP + database).
• terminal / command line: controlling the computer with text. On Windows cmd, on sigma through PuTTY.
• SSH: a secure connection to a remote server through the command line.
• SFTP: file transfer to the server over the same secure connection. Used by WinSCP and VS Code.
• VPN: a tunnel into the university network. Without it you cannot reach sigma from home.
• Kubeflow: the university cloud where our VS Code runs. Opens in the browser.
• VS Code: the editor we write code in.
• Git: a tool that tracks changes in files. GitHub: the website those changes are sent to.
• repository (repo): a project folder managed by Git.
• commit: a saved version of changes with a description. push: sending commits to GitHub.
• 2FA: two-factor authentication, a code from your phone when signing in.

How a page gets into the browser

1. You type a URL into the browser.
2. The browser sends the server an HTTP request: "give me /student/name.surname/index.html".
3. The server finds the file (static page) or builds it with a PHP script (dynamic page).
4. The server sends the HTML back. The browser fetches CSS, images and JavaScript and renders the page.

The whole course is about what happens in steps 3 and 4.

What runs where

A file saved in VS Code is uploaded to sigma automatically over SFTP. You never edit code directly on the server.

Command line

You will need a few commands every week. Windows (cmd) and Linux (sigma) differ:

Example 1: from file path to URL

On sigma you have a home folder. The web server only sees what is in public_html:

/home/jn123ab/
└── public_html/            ->  https://sigma.tuke.sk/student/name.surname/
    └── ti/
        └── cv01/
            └── index.html  ->  https://sigma.tuke.sk/student/name.surname/ti/cv01/

Example 2: first commands on sigma

pwd
mkdir -p public_html/ti/cv01
cd public_html/ti/cv01
ls -l

After these commands the folder exists where we will put the first HTML file next week.

Example 3: this is what our first file will look like

We will write it together next week. For today just notice that the browser reads plain text.

<!doctype html>
<html lang="sk">
<head>
  <meta charset="utf-8">
  <title>Moja prvá stránka</title>
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <h1>Ahoj, web!</h1>
  <p class="intro">Toto je moja prvá stránka na sigme.</p>
</body>
</html>

body { font-family: sans-serif; max-width: 40rem; margin: 2rem auto; }
.intro { color: #a3274f; }