composer/doc/create-projects.md

# Create Projects

You can use Composer to create new projects from an existing package. There are several applications for this:

1. You can deploy application packages.
2. You can check out any package and start developing on patches for example.
3. Projects with multiple developers can use this feature to bootstrap the initial application for development.

To create a new project using composer you can use the "create-project", pass it a package name + version and a directory to create the project in. The directory is not allowed to exist, it will be created during installation.

    php composer.phar create-project doctrine/orm 2.2.0 /path/to/new-project

By default the command checks for the packages on packagist.org. To change this behavior you can use the --repository-url parameter and either point it to an HTTP url for your own packagist repository or to a packages.json file.

If you want to get a development version of the code directly checked out from version control you have to add the --prefer-source parameter.