# Installing Composer with PHP Composer is the standard tool for managing PHP dependencies. It automates library installation, enforces version constraints, and helps organize autoloading, making it an essential part of modern PHP development. Whether you're building with frameworks like Laravel, Symfony, or Slim, Composer ensures consistency across environments and simplifies dependency resolution. This guide covers installing Composer with a specific PHP version on a Linux system — useful when working across multiple PHP projects or servers that require different runtime versions. By the end, you'll have Composer installed safely, bound to a specific PHP version such as PHP 8.4, and a reusable alias set up for scripting or interactive use, following PHP dependency management practices documented in [**Vultr Docs**](https://docs.vultr.com/how-to-install-composer-with-php). * * * ## Prerequisites * Access to a Linux instance. * SSH access to the server. * A non-root user with `sudo` privileges. * The server's package index already updated. * * * ## Install PHP Install PHP, the command-line interface (CLI), and required tools such as `curl` and `unzip` using your distribution's package manager. ### Install PHP on Ubuntu and Debian **1\. Install the default PHP version and required utilities on APT-based systems:** ```console sudo apt install -y php php-cli curl unzip ``` To install a specific PHP version (such as 8.3 or 8.4), add a third-party repository — the Ondřej Surý PPA on Ubuntu, or the SURY repository on Debian. These repositories provide maintained versions of PHP not available in the default APT sources. ### Install PHP on Rocky Linux and AlmaLinux **1\. Install PHP and required tools on DNF-based distributions:** ```console sudo dnf install -y php php-cli curl unzip ``` To install a specific PHP version, enable the EPEL and Remi repositories. These repositories offer multiple PHP versions for RHEL-based systems including Rocky Linux and AlmaLinux. * * * ## Install Composer Using a Specific PHP Version > **Note:** This guide uses PHP 8.4 as the example version. On DNF-based distributions (like Rocky Linux or AlmaLinux), the system uses `php` as the command unless `update-alternatives` is configured. If `php8.4` doesn't work, use `php` instead. **1\. Download the Composer installer using PHP 8.4:** ```console php8.4 -r "copy('https://getcomposer.org/installer', 'composer-setup.php');" ``` **2\. Get the installer signature.** This ensures the installer is authentic and has not been tampered with: ```console curl -s https://composer.github.io/installer.sig ``` Copy the hash from the output. You'll need it for verification in the next step. **3\. Verify the installer.** Replace `your_hash_here` with the hash you copied: ```console php8.4 -r "if (hash_file('sha384', 'composer-setup.php') === 'your_hash_here') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;" ``` Output: ```plaintext Installer verified ``` **4\. Run the Composer installer using PHP 8.4 and install it system-wide:** ```console sudo php8.4 composer-setup.php --install-dir=/usr/local/bin --filename=composer ``` **5\. Clean up the installer file:** ```console rm composer-setup.php ``` **6\. Verify the Composer installation:** ```console composer ``` Output: ```plaintext ______ / ____/___ ____ ___ ____ ____ ________ _____ / / / __ \/ __ `__ \/ __ \/ __ \/ ___/ _ \/ ___/ / /___/ /_/ / / / / / / /_/ / /_/ (__ ) __/ / \____/\____/_/ /_/ /_/ .___/\____/____/\___/_/ /_/ Composer version 2.8.8 2025-04-04 16:56:46 ``` * * * ## Run Composer with a Specific PHP Version To run Composer with a specific PHP version (like PHP 8.4), configure your environment as follows. **1\. Confirm the path of the PHP 8.4 binary:** ```console which php8.4 ``` Output: ```plaintext /usr/bin/php8.4 ``` **2\. Run Composer using the PHP 8.4 binary:** ```console php8.4 /usr/local/bin/composer ``` **3\. Create an alias so** `composer` **always runs with PHP 8.4 (optional):** ```console echo 'alias composer="php8.4 /usr/local/bin/composer"' >> ~/.bashrc ``` For portability in scripts or cron jobs, consider using a shebang like `#!/usr/bin/env php` instead of hardcoding a version path. **4\. Reload your shell configuration to apply the alias:** ```console source ~/.bashrc ``` If you're using Zsh, replace `~/.bashrc` with `~/.zshrc`. **5\. Verify that Composer now runs with PHP 8.4:** ```console composer --version ``` Output: ```plaintext Composer version 2.8.8 2025-04-04 16:56:46 PHP version 8.4.0 (/usr/bin/php8.4) Run the "diagnose" command to get more detailed diagnostics output. ``` For managing multiple Composer versions or isolating global dependencies per PHP version, consider tools like `cgr`, `composer-bin`, or `asdf`. ### Test Composer Functionality (Optional) To confirm that Composer is functional and can generate project scaffolding: **1\. Run** `composer init` **in non-interactive mode to generate a minimal** `composer.json`**:** ```console composer init --name=test/app --description="Test app" --author="Your Name" --require=php:^8.4 --no-interaction ``` **2\. View the generated file to confirm success:** ```console cat composer.json ``` Output: ```plaintext { "name": "test/app", "description": "Test app", "require": { "php": "^8.4" } } ``` You can now run `composer install` or add additional dependencies to begin building your PHP project. * * * ## Next Steps You now have Composer installed on your Linux system, bound to a specific PHP version such as PHP 8.4, with a reusable alias for convenience. From here, you can: * Run `composer require` to add your first dependencies to a real project * Set up global tool isolation or multi-version workflows with `cgr`, `composer-bin`, or [asdf](https://asdf-vm.com/) * Add Composer's `vendor/` directory to your `.gitignore` and commit `composer.lock` for reproducible installs * Read the [official Composer documentation](https://getcomposer.org/doc/) to learn more about autoloading and dependency constraints For the full guide with additional tips, visit the original article on [**Vultr Docs**](https://docs.vultr.com/how-to-install-composer-with-php).