All composer commands, depending on your install, may need to use php composer.phar in the install folder for composer, instead of plain composer.

Installing dependencies

Command Description
composer install Downloads and installs all the libraries and dependencies outlined in the composer.lock file. If the file does not exist it will look for composer.json and do the same, creating a composer.lock file.
composer install --dry-run Simulates the install without installing anything

This command doesn’t change any file. If composer.lock is not present, it will create it.

composer.lock should always be committed to the repository. It has all the information needed to bring the local dependencies to the last committed state. If that file is modified on the repository, you will need to run composer install again after fetching the changes to update your local dependencies to those on that file.

Updating packages

Command Description
composer update Updates all packages
composer update --with-dependencies Updates all packages and its dependencies
composer update vendor/package Updates a certain package from vendor
composer update vendor/* Updates all packages from vendor
composer update --lock Updates composer.lock hash without updating any packages

This command changes only the composer.lock file.

Updating autoloader

Command Description
composer dumpautoload -o Generates optimized autoload files

Adding packages

Command Description
composer require vendor/package. Adds package from vendor to composer.json’s require section and installs it
composer require vendor/package --dev Adds package from vendor to composer.json’s require-dev section and installs it.

This command changes both the composer.json and composer.lock files.

Removing packages

Command Description
composer remove vendor/package Removes vendor/package from composer.json and uninstalls it

This command changes both the composer.json and composer.lock files.

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