Editing File-system permissions (section)

===Classes===
The classes determine how permissions map to a user. The ''user class'' permissions apply to the user who owns the file. The ''group class''  permissions apply to users of the file's owning [[Group identifier|group]]. The ''others class'' applies to other users. 

The ''effective permissions'' are the permissions of the class in which the user falls ''first'' given the order: user, group then others. For example, the owning user has effective permissions of the user class even if they are in the owning group.