Recursively Chmod

Change chmod for all files and folders in concrete folder:
chmod -R 755 /srv/folder

Go to the folder in which you need to change chmod rights.
Change chmod for all files:
find . -type f -exec chmod 644 {} \;

Change chmod for all folders:
find . -type d -exec chmod 755 {} \;

Change chmod for all files and folders:
chmod -R 777 .

 

Recursively Chown

Change chown user and group for all files and folders as www-data:
chown -R www-data:www-data *