sudo chown
sudo chown <owner>[:<group>] <path>
Risk: Careful
What it does
Hands a file or folder to another owner (and group). Needs root.
When to use it
When a service user, like www-data, must write somewhere.
Example
$ sudo chown www-data:www-data uploadsGive the uploads folder to the web staff.
$ sudo chown -R www-data:www-data uploadsThe folder and everything inside. Check the path twice.
Learn it in: Change the owner: chown · Official docs