How to install a LEMP stack on Debian 12

To set up a LEMP stack (Linux, Nginx, MySQL, PHP) on Debian 12, you'll need to follow these steps:

Update the System: Log in to your Debian 12 server as a user with sudo privileges and update the system packages to the latest versions:
```
sudo apt update
sudo apt upgrade
```
Install Nginx: Install the Nginx web server using the following command:
```
sudo apt install nginx
```
After installation, start the Nginx service and enable it to start on boot:
```
sudo systemctl start nginx
sudo systemctl enable nginx
```
You can verify Nginx's status to ensure it's running without errors:
```
sudo systemctl status nginx
```
Install MySQL (MariaDB): Install the MySQL database server (Debian 12 uses MariaDB as a drop-in replacement for MySQL):
```
sudo apt install mariadb-server
```
After installation, start the MariaDB service and enable it to start on boot:
```
sudo systemctl start mariadb
sudo systemctl enable mariadb
```
Secure your MariaDB installation by running the following script:
```
sudo mysql_secure_installation
```
This script will prompt you to set a root password, remove anonymous users, disallow remote root login, and more. Follow the prompts and answer accordingly.
Install PHP: Install PHP and the required PHP modules for common applications:
```
sudo apt install php php-fpm php-mysql
```

Configure Nginx to Use PHP-FPM: Next, you'll configure Nginx to use PHP-FPM to process PHP files. Create a new server block configuration for your website:

sudo nano /etc/nginx/sites-available/example.com

Replace "example.com" with your domain or website name. In this file, add the following configuration (you can modify it according to your needs):

server {
    listen 80;
    server_name example.com www.example.com;
    root /var/www/html;

    index index.php index.html index.htm;

    location / {
        try_files $uri $uri/ =404;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php-fpm.sock;
    }
}

Save the file and create a symbolic link to enable the server block:

sudo ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/

Test the Nginx configuration and restart the service:

sudo nginx -t
sudo systemctl restart nginx

Test PHP-FPM: Create a PHP info file to test if PHP-FPM is working correctly:
```
echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php
```
Open a web browser and visit http://your_server_ip/info.php. You should see the PHP info page with PHP configuration details.
Firewall (Optional): If you have a firewall enabled, make sure to allow HTTP (port 80) and HTTPS (port 443) traffic to your server to access your website.

That's it! You now have a LEMP stack (Linux, Nginx, MySQL, PHP) set up on your Debian 12 server. You can now deploy your web applications and websites.