Groups allow sets of users to share files. The group permissions
on a file or directory determine whether members of a group can
You can set the group of a file or directory by changing its properties from the Desktop or by using the chgrp(C) command. For more information on properties, see ``Controlling file permissions'' in Using the Desktop.
A user can be a member of several groups at once, and can access any file or directory that is within their group set (if group permissions allow). This membership set is known as the supplemental group list. By default, files created by a user have the group ID of their login group. Users can change their current working group (also known as effective group ID) or manipulate their supplemental group list with the sg(C) command.