Basic Permissions

The term basic permissions refers to the traditional UNIX scheme for protecting files and folders (directories) regarding three types of access:

• read permission - lets a user read the contents of a file or, if a folder, list the files in the folder

• write permission - lets a user make changes to a file, or, if a folder, add or delete files

• execute permission - lets a user run the file if it is executable or, if a folder, read or search its files

If access to a folder is limited, the File Manager displays special icons to show that a folder is inaccessible or read-only (see figure below).

Figure 5-4 Special File Manager Icons

Permissions are granted according to three classes of user:

• owner - the user who created the file or folder (or received ownership through chown(1) ), usually with the greatest degree of access

• group - the set of users to which the owner belongs, with common needs of access to the file or folder

• other - all other users that are not the owner or in the owner's group