Group control is carried out using the sg(C) (supplementary group) command. Type id (see ``Finding out your group'') or sg to obtain a list of the groups of which you are a member, as follows:
$ sg Current effective supplemental groups: 1014(techpubs)You can change your current group by using the sg -g option, as follows:
$ sg -g techpubsYou must be recognized as a member of the new group before you can switch to it. Group memberships are listed in the file /etc/group; each group has a line in the file, followed by the names of those users who are authorized to work in it. After successfully changing group, you work within the new group for the remainder of the login session (or until you run sg -g again).