How to Install PHP Composer on Debian 11

Some PHP-based applications require extra libraries or components that you need to manage. Manual management is a very time-consuming and tedious process, but Composer can help.

Composer is a dependency manager for PHP that helps developers to manage dependencies used in a PHP project. It provides an easier way to specify the set of all required libraries and dependencies of your project and install them. It is used by Symfony and Laravel to bootstrap new projects.

In this post, we will explain how to install PHP Composer on Debian 11.

Step 1 – Install PHP Composer on Debian 11

Before installing Composer, PHP and some other extensions must be installed to your system. You can install all of them by running the following command:

apt-get install php php-common php-cli php-curl php-intl php-zip git curl unzip -y

Once all the packages are installed, run the following command to install Composer:

php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');" 
php composer-setup.php --install-dir=/usr/local/bin --filename=composer

You will get the following output:

All settings correct for using Composer
Downloading...

Composer (version 2.1.14) successfully installed to: /usr/local/bin/composer
Use it: php /usr/local/bin/composer

Next, set the executable permission to the Composer binary using the command below:

chmod +x /usr/local/bin/composer

Next, verify the Composer version using the following command:

composer --version

You will get the following output:

Composer version 2.1.14 2021-11-30 10:51:43

Step 2 – How to Use PHP Composer

In this section, we will show you how to use Composer.

To list all options available with Composer, run the following command:

composer

You will get the following output:

Continue as root/super user [yes]? yes
   ______
  / ____/___  ____ ___  ____  ____  ________  _____
 / /   / __ \/ __ `__ \/ __ \/ __ \/ ___/ _ \/ ___/
/ /___/ /_/ / / / / / / /_/ / /_/ (__  )  __/ /
\____/\____/_/ /_/ /_/ .___/\____/____/\___/_/
                    /_/
Composer version 2.1.14 2021-11-30 10:51:43

Usage:
  command [options] [arguments]

Options:
  -h, --help                     Display this help message
  -q, --quiet                    Do not output any message
  -V, --version                  Display this application version
      --ansi                     Force ANSI output
      --no-ansi                  Disable ANSI output
  -n, --no-interaction           Do not ask any interactive question
      --profile                  Display timing and memory usage information
      --no-plugins               Whether to disable plugins.

Now, let’s create a project directory and install some packages.

First, create a directory named app using the following command:

mkdir app

Next, navigate to the app directory and install the carbon package using the following command:

cd app
composer require nesbot/carbon

After the installation, list all files and directories created by the package using the following command:

ls -l

You will get the following output:

-rw-r--r-- 1 root root    60 Dec 17 05:22 composer.json
-rw-r--r-- 1 root root 18462 Dec 17 05:22 composer.lock
drwxr-xr-x 6 root root  4096 Dec 17 05:22 vendor

Now, create a sample application using the following command:

nano sample.php

Add the following lines:

<?php

require __DIR__ . '/vendor/autoload.php';

use Carbon\Carbon;

printf("Now: %s", Carbon::now());

Save and close the file, then run the PHP application using the following command:

php sample.php

You should see the following output:

Now: 2021-12-17 05:22:44

To update all the dependencies, run the following command:

composer update

To remove the installed package, run the following command:

composer remove nesbot/carbon

You should see the following output:

  - Removing symfony/translation-contracts (v2.5.0)
  - Removing symfony/translation (v5.4.1)
  - Removing symfony/polyfill-php80 (v1.23.1)
  - Removing symfony/polyfill-mbstring (v1.23.1)
  - Removing symfony/deprecation-contracts (v2.5.0)
  - Removing nesbot/carbon (2.55.2)
Generating autoload files

Step 3 – How to Upgrade PHP Composer

If you want to upgrade Composer to the latest version, run the following command:

composer self-update

You should see the following output:

You are already using the latest available Composer version 2.1.14 (stable channel).

As you can see, the Composer is already in the latest version. If any newer version is available, you will be prompted after running the self-update command.

Conclusion

In the above guide, you learned how to install PHP Composer on Debian 11. You also learned how to use Composer to install and manage the PHP dependencies. Try using it to manage your PHP project on dedicated hosting from Atlantic.Net!