Linux System - Table 12 > Packages - Table 4 > attr

\"Extended attributes are name:value pairs associated permanently with files and directories, similar to the environment strings associated with a process. An attribute may be defined or undefined. If it is defined, its value may be empty or non-empty. Extended attributes are extensions to the normal attributes which are associated with all inodes in the system (i.e. the stat(2) data). They are often used to provide additional functionality to a filesystem - for example, additional security features such as Access Control Lists (ACLs) may be implemented using extended attributes.\"