Composer 报 file_put_contents 错误，怎么办，咋办，求帮助

Try this:

sudo chmod -R 664 /home/vagrant/.composer/cache

chmod以后成这样了
Cannot create cache directory /home/vagrant/.composer/cache/repo/https---packagist.laravel-china.org/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/vagrant/.composer/cache/files/, or directory is not writable. Proceeding without cache

加上二楼说的，把这个也试试：
sudo chown -R $(whoami):$(id -gn) .
还不行，你就得告诉我你用的什么系统了……