removing a user from a group

[Stu]

I have the following user in two groups (see below) and I want to
remove this
user from group staff, which is my default group for all users.

/tmp/ groups
staff dba

I know I can open /etc/group file and remove that way but there are so
many users
in the group, when I open it with the vi editor the line is way too
long to edit.

Is there a command on AIX that will allow me to remove a user from a
particular
group. In addition, where is the default group "staff" defined. Just
curious about
that. I use mkuser to add users to the system is "staff" the default
group for that
command?

Thanks in advance to all who answer this post.

[Henry]

this will show your the primary group and the groups than user
"username" belongs to
lsuser -a pgrp groups username

the primary group of a user is shown in the /etc/passwd file (or use
the lsuser command)

To find the group id of the "staff" group - awk can test that the 3rd
field is the string "staff" and print the 1st field (the id)
awk -F':' '$1 == "staff" {print $3} ' /etc/group
or
lsgroup staff

so we can see the (group) id of the "staff" group is 1

if you want to see which users have a *primary* group of "staff"
awk -F':' '$4 == "1" {print $1} ' /etc/passwd

so. If your user has a primary group of "staff" and you want to remove
this, then change the primary group to something else, your example
has the group "dba"
[as root]
chuser pgrp=dba username

I'd be a bit careful about removing "staff" but that's your choice.

The "staff" group is defined as part of the standard installation in /
etc/group

yes, "staff" is the default, but you can change this. If you look
through the mkuser man page you will get some hints under the "Files"
section

[Mark van Huijstee]

man chgrpmem