To change permission by type (directory or file), the easiest way can do it is using find command and do something as a follow up action.
To change permission for file by 0664,
find ./ -type f -exec chmod -v 0664 {} \;
Note that you should put space between {} and \
To change permission for directory by 0775
find ./ - type d -exec chmod -v 0775 {} \;