Permissions

Use these settings to specify the read/write/execute permissions (in octal) assigned to each item, as well as the item's group and user IDs.

File Permissions
A three digit octal number that specifies the read, write, and execute permissions assigned to files.
Group ID
The ID of the group. The /etc/password file contains the mapping information for the name (the corresponding group name and group number). The root is always 0.
User ID
The ID associated with a user. The /etc/group file contains the mapping information for the user ID (the corresponding user name, user number, and group number). The root is always 0.