permitted, - if it is not. w if writing is permitted, - if it is not. x if execution is permitted, - if it is not. The following are some examples of symbolic notation: -rwxr-xr-x: a regular file whose user class has full permissions and whose group and others classes have only the read and execute permissions. crw-rw-r--: a character special file whose user and group classes have the read and write permissions and whose others class has only the read permission. dr-x------: a directory whose user class has read and execute permissions and whose group and others classes have no permissions. In some permission systems additional symbols in the ls -l display represent additional permission features: + (plus) suffix indicates an access control list that can control additional permissions. . (dot) suffix indicates an SELinux context is present. Details may be listed with the command ls -Z. @ suffix indicates extended file attributes are present. To represent the setuid, setgid and sticky or text attributes, the executable character (x or -) is modified. Though these attributes affect the overall file, not only users in one class, the setuid attribute modifies the executable character in the triad for the user, the setgid attribute modifies the executable character in the triad for the group and the sticky or text attribute modifies the executable character in the triad for others. For the setuid or setgid attributes, in the first or second triad, the x becomes s and the - becomes S. For the sticky or text attribute, in the third triad, the x becomes t and the - becomes T. Here is an example: -rwsr-Sr-t: a file whose user class has read, write and execute permissions; whose group class has read permission; whose others class has read and execute permissions; and which has setuid, setgid and sticky attributes set. Numeric notation Another method for representing Unix permissions is an octal (base-8) notation as shown by stat -c %a. This notation consists of at least three digits. Each of the three rightmost digits represents a different component of the permissions: owner, group, and others. (If a fourth digit is present, the leftmost (high-order) digit addresses three additional attributes, the setuid bit, the setgid bit and the sticky bit.) Each of these digits is the sum of its component bits in the binary numeral system. As a result, specific bits add to the sum