id
From NetBSD Wiki
id -- return user identity
The id(1) utility displays the user and group names and numeric IDs, of the calling process, to the standard output. If the real and effective IDs are different, both are displayed, otherwise only the real ID is displayed.
# id uid=0(root) gid=0(wheel) groups=0(wheel),2(kmem),3(sys),4(tty),5(operator),20(staff),31(guest)
% id uid=1000(john) gid=100(users) groups=0(wheel),100(users)
