Owners, Groups, and Permissions
File permissions and file ownership are important components of UNIX because they provide a secure method for storing files. Every file in UNIX has the following attributes:
Other (world) permissions
The owner's permissions determine which actions the owner of the file can perform on the file. The group's permissions determine which actions a user, who is a member of the group that a file belongs to, can perform on the file. The permissions for others indicate which action all other users can perform on the file.
The actions that can be performed on a file are read, write, and execute. If a user has read permissions, that user can view the contents of a file. A user with write ...