The immediately noticeable difference between vi and other editors is that when vi launches you can't just start typing text.

The Disks app takes over some more challenging commands, such as fsck, mount, parted, chown, and dd. This app is a handy GUI that also prevents you from having to edit the fstab configuration file ...

Permissions have two parts: an action and a set of users. The three actions—read, write, and execute—define what can be done to a file, while the user sets define who can do it.