How do I change the permissions of a folder and all its subfolders and files?
This only applies to the /opt/lampp/htdocs folder, not its contents:
chmod 775 /opt/lampp/htdocs
How do I set chmod 755 for all of the /opt/lampp/htdocs folder's current contents, as well as automatically in the future for new folders/files created under it?
Related: How can I set a default 'chmod' in a Linux terminal?