Cannot create cache directory .. or directory is not writable. Proceeding without cache in Laravel
When you installed composer pretty sure you used $ sudo command because of that the ~/.composer folder was created by the root.
Run this to fix the issue:
$ sudo chown -R $USER $HOME/.composer
Change the group permission for the folder
sudo chown -R w3cert /home/w3cert/.composer/cache/repo/https---packagist.organd the Files folder too
sudo chown -R w3cert /home/w3cert/.composer/cache/files/I'm assuming w3cert is your username, if not change the 4th parameter to your username.
If the problem still persists try
sudo chown -R w3cert /home/w3cert/.composerNow, there is a chance that you won't be able to create your app directory, if that happens do the same for your html folder or the folder you are trying to create your laravel project in.
Change ownership of your .composer directory:
sudo chown -R $USER $HOME/.composer$USER is your username and $HOME is your home directory.