Access Control Lists

OR

Default Permissions

This is a how-to specifically for whats called ACL’s or Access Control Lists. These dictate the default Username, Groupname, and/or permissions that apply to the top directory and back down, as you so choose. This is awesome for when you mount secondary hard drives, or will be using a directory as a shared folder and need unified permissions.

tl;dr

sudo setfacl -Rdm u:usernamehere:rwx /path/to/file
sudo setfacl -Rm u:usernamehere:rwx /path/to/file
sudo setfacl -Rdm g:groupnamehere:rwx /base/path/members/
sudo setfacl -Rm g:groupnamehere:rwx /base/path/members/

setfacl is to set the acl. -R is for recursively acting on all files from /whatever/file down d is for default, setting the defaults first time round m is for “modifying” the acl

Then, to make sure all files, recursively, receive the update, run it again without the d