I am getting this message when creating a new project Cannot create cache directory /home/cmnd/.composer/cache/repo/https---repo.packagist.org/, or directory is not writable. Proceeding without cache
That's not an error, but a Composer warning, saying that it can't create its cache folder at /home/cmnd/.composer/cache/repo/https---repo.packagist.org/ (probably because of a permissions issue.
You can ignore it, but Composer will just run slower.