Operating System User's Guide
Chapter 3, Working with files and directories

Finding out your group

Finding out your group

In order to find out the groups of which you are a member, use the id(C) command, as follows: 

   $ id
   uid=13052(johnd) gid=1014(techpubs)
The command displays your numeric user identification (UID) and your group identification (GID). Your login and group names are given in parentheses.