How To Install and Use Composer on Ubuntu 20.04

Composer is a dependency manager for PHP, allowing you to manage your project's libraries and packages effortlessly. If you're developing PHP applications, Composer is an essential tool. This guide will show you how to install and use Composer on Ubuntu 20.04.

Prerequisites

Before you start, make sure you have the following:

• An Ubuntu 20.04 server.
• A user with sudo privileges.

• PHP installed on your server. If PHP is not installed, you can do so by running:
  

  sudo apt update
  sudo apt install php-cli unzip
  

Step 1: Install Composer

1.1 Update Your Package Manager

First, update the package manager cache:

sudo apt update

1.2 Download the Composer Installer

Next, download the Composer installer script using curl:

curl -sS https://getcomposer.org/installer -o composer-setup.php

1.3 Verify the Installer

Verify that the installer matches the SHA-384 hash for the latest installer found on the Composer Public Keys/Signatures page. Replace <HASH> with the latest hash:

HASH=`curl -sS https://composer.github.io/installer.sig`
php -r "if (hash_file('sha384', 'composer-setup.php') === '$HASH') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"

If the output says "Installer verified", you can proceed. If it says "Installer corrupt", then the script should be redownloaded.

1.4 Install Composer

Run the installer script:

sudo php composer-setup.php --install-dir=/usr/local/bin --filename=composer

This command installs Composer globally, making it accessible from any directory.

1.5 Verify the Installation

To verify the installation, run:

composer --version

You should see output similar to:

Composer version 2.x.x 2021-xx-xx xx:xx:xx

Step 2: Using Composer

2.1 Create a PHP Project

Navigate to your project directory:

cd /path/to/your/project

2.2 Initialize a New Project

To start a new project, run:

composer init

Follow the prompts to set up your project's composer.json file.

2.3 Install Dependencies

To install a package (e.g., Monolog for logging), run:

composer require monolog/monolog

This command downloads and installs the package into the vendor directory and updates composer.json with the new dependency.

2.4 Update Dependencies

To update your project's dependencies, run:

composer update

2.5 Autoloading

Composer provides an autoloader to manage your PHP classes. Include the following line at the beginning of your PHP scripts to use it:

require 'vendor/autoload.php';

Conclusion

You've now installed and configured Composer on your Ubuntu 20.04 server. Composer simplifies dependency management in PHP, making your development process more efficient. For more information on using Composer, check out the official Composer documentation.

Happy coding!