remove (delete) folder and its coontent in ubuntu terminal

sudo rm -r

copy content of folder to another folder

see what owner of files is (for sake).

sudo cp -a /source/. /dest/

this should copy all files and in my case assign right owner.
If not cd to the dest folder and use

sudo chown www-data:www-data *

Nginx test && reload

sudo nginx -t && sudo nginx -s reload