Composer is a package manager for PHP.

Install

Read the installation docs.

# Install
php composer.phar install

# Alternate install
# See: http://stackoverflow.com/questions/21670709/could-not-open-input-file-composer-phar-error-in-symfony2-using-wamp
curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

Moving composer.phar into /user/local/bin/composer makes it available from any directory. Make sure this directory is added to your shell’s PATH environment variable.

Update

# Requires sudo to write
sudo composer self-update

Usage

Install packages

Install the exact package versions specified in composer.lock. This should be used immediately:

• After project setup
• After changing Git branches

composer install

Update packages

Updates all packages, their dependenices, and composer.lock.

composer update

Update specific packages

Updates a specific package, its dependencies, and composer.lock.

composer update {namespace}/{packageName}

Troubleshooting

Missing GMP extension

Composer requires PHP + GMP extension to execute. The PHP library in your shell’s PATH may not include that. Switch PHP versions:

1. Develop > Command Line > PHP
2. Try running composer install again.