Using multiple PHP versions on Ubuntu is straightforward, as Ubuntu allows you to install multiple versions of PHP side by side. You can switch between them using tools like update-alternatives. Here’s a step-by-step guide:

1️⃣ Install Multiple PHP Versions

1. Update Package List: sudo apt update
2. Add the Ondřej PPA (if not already added): The Ondřej PPA provides multiple PHP versions. sudo add-apt-repository ppa:ondrej/php sudo apt update
3. Install the PHP Versions You Need: For example, to install PHP 8.1 and PHP 8.2: sudo apt install php8.1 php8.1-cli php8.1-fpm php8.1-mbstring php8.1-xml php8.1-curl php8.1-zip sudo apt install php8.2 php8.2-cli php8.2-fpm php8.2-mbstring php8.2-xml php8.2-curl php8.2-zip

2️⃣ Configure update-alternatives to Manage PHP Versions

update-alternatives is a tool to manage multiple versions of the same command.

1. Set Alternatives for PHP: sudo update-alternatives --install /usr/bin/php php /usr/bin/php8.1 81 sudo update-alternatives --install /usr/bin/php php /usr/bin/php8.2 82
2. Switch PHP Versions Manually: Run the following command and select the version you want to use: sudo update-alternatives --config php You’ll see a list of installed PHP versions, for example: There are 2 choices for the alternative php (providing /usr/bin/php). Selection Path Priority Status ------------------------------------------------------------ 1 /usr/bin/php8.1 81 manual mode 2 /usr/bin/php8.2 82 manual mode Press <enter> to keep the current choice[*], or type selection number: Enter the number corresponding to the PHP version you want to use.
3. Verify the Active PHP Version: php -v

3️⃣ Configure Different PHP Versions for Apache

If you’re using Apache as your web server and want different sites to use different PHP versions:

1. Enable the PHP Modules for Apache: sudo a2dismod php8.1 # Disable the current PHP version sudo a2enmod php8.2 # Enable the desired PHP version sudo systemctl restart apache2
2. Set PHP Version Per Virtual Host: If you have multiple sites and want each to use a different PHP version:
   • Open the virtual host configuration file for your site: sudo nano /etc/apache2/sites-available/your-site.conf
   • Add the following lines inside the <VirtualHost> block for the desired PHP version: <FilesMatch \.php$> SetHandler "proxy:unix:/run/php/php8.1-fpm.sock|fcgi://localhost/" </FilesMatch>
   • For another site, use: <FilesMatch \.php$> SetHandler "proxy:unix:/run/php/php8.2-fpm.sock|fcgi://localhost/" </FilesMatch>
3. Restart Apache: sudo systemctl restart apache2

4️⃣ Configure PHP Versions for Nginx

If you’re using Nginx, configure the desired PHP version per server block.

1. Edit Your Server Block File: sudo nano /etc/nginx/sites-available/your-site.conf
2. Update fastcgi_pass to Use the Desired PHP Version:
   • For PHP 8.1: location ~ \.php$ { include snippets/fastcgi-php.conf; fastcgi_pass unix:/run/php/php8.1-fpm.sock; }
   • For PHP 8.2: location ~ \.php$ { include snippets/fastcgi-php.conf; fastcgi_pass unix:/run/php/php8.2-fpm.sock; }
3. Restart Nginx and PHP-FPM: sudo systemctl restart nginx sudo systemctl restart php8.1-fpm php8.2-fpm

5️⃣ CLI-Level Per-Project PHP Version

To use a specific PHP version in a project without changing the global configuration:

1. Run the PHP version directly: php8.1 artisan serve php8.2 artisan serve
2. Use tools like Symfony’s Local PHP Version: Install Symfony CLI: curl -sS https://get.symfony.com/cli/installer | bash export PATH="$HOME/.symfony/bin:$PATH" Set the PHP version per directory: symfony local:php:set 8.1

6️⃣ Verify PHP Versions

• Check the installed PHP versions: ls /usr/bin/php*
• Verify active PHP CLI version: php -v

Summary

1. Install multiple PHP versions (e.g., PHP 8.1, 8.2).
2. Use update-alternatives to switch between PHP versions for CLI.
3. Configure Apache/Nginx to use specific PHP versions for individual sites.
4. Use per-project settings for PHP CLI if required.

Let me know if you need help configuring anything! 🚀