Installing Composer

We will install Composer in a Linux environment.

What is Composer?

Composer is a tool for managing PHP library dependencies used in your project.
It installs the libraries you want to use, including any dependencies those libraries require.
Composer creates a vendor directory and installs the required libraries into that directory.

Environment

Debian GNU/Linux 12 (bookworm)
PHP 8.2.17、PHP 8.3.4

1. Install Composer

Run the following commands to install the latest version of Composer.
Replace <installer checksum> with the “Installer Checksum” from the Composer Public Keys / Checksums page.
<current directory> will show your current working directory.

# php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
# php -r "if (hash_file('sha384', 'composer-setup.php') === '<installer checksum>') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
Installer verified
# php composer-setup.php
All settings correct for using Composer
Downloading...

Composer (version 2.7.2) successfully installed to: <current directory>/composer.phar
Use it: php composer.phar
# php -r "unlink('composer-setup.php');"
# mv composer.phar /usr/local/bin/composer

Here’s what each command does:

php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');" downloads the Composer installer to your current directory.

php -r "if (hash_file('sha384', 'composer-setup.php') === '<installer checksum>') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;" verifies the installer by comparing its hash with the expected checksum. If it matches, the installer is valid.

php composer-setup.php runs the installer to install Composer.

php -r "unlink('composer-setup.php');" deletes the installer, as it’s no longer needed.

mv composer.phar /usr/local/bin/composer moves the Composer executable to a directory included in your system’s PATH, so you can use the composer command without specifying the full path.
You may need root privileges for this command. Run it as the root user or prepend sudo like this:
sudo mv composer.phar /usr/local/bin/composer
You can use a different directory, such as /usr/bin, if it’s included in your PATH.

2. Verify the Installation

To confirm that Composer was successfully installed, check its version by running:

# composer -v
   ______
  / ____/___  ____ ___  ____  ____  ________  _____
 / /   / __ \/ __ `__ \/ __ \/ __ \/ ___/ _ \/ ___/
/ /___/ /_/ / / / / / / /_/ / /_/ (__  )  __/ /
\____/\____/_/ /_/ /_/ .___/\____/____/\___/_/
                    /_/
Composer version 2.7.2 2024-03-11 17:12:18

Composer has been successfully installed.