All of the files on a Linux system have permissions that allow or prevent others from viewing, modifying or executing them. The superuser "root" has the ability to access any file on the system. Each file has access restrictions, user restrictions, and an owner/group association.

Every file is secured by the following three layers of permissions, in order of importance:

Inside each of the three sets of permissions are the actual permissions. The permissions, along with the way they apply differently to files and directories, are outlined below:

To view and edit the permissions on files and directories, open the System Menu->Home Folder, right-click on a file or directory, then select Properties. The permissions are found under the Permissions tab and allow for the editing of all permission levels, if you are the owner of the file. Advanced permission settings (such as in the Advanced Permissions tab) are outside of the scope of this guide.