This permission scheme will avoid the “Unable to save – Permission denied – File is Read only” error when you try to save a file in your local /var/www/html/ directory. This will let you edit “Read only” files by adding you to the www-data group and granting the group permission to write to the files.
First, add your user to the www-data Apache group (replace ‘username’ with your own):
sudo usermod -aG www-data username
Note: The -aG option above will add you to that group and also keep your memberships to other groups.
After doing the line above, you should log out of your system and back in for the “usermod” to take effect.
Run this to grant ownership to the www-data Apache group, which you are now a part of:
sudo chown -R www-data:www-data /var/www/html
Assign these files to the www-data group, if it’s not already done:
sudo chgrp -R www-data /var/www/html
Grant permission for owner and group to read, write, and execute (do this at your own risk):
sudo chmod -R 775 /var/www/html