Is that redundant for groups=0(root) listed in id command output? sudo id uid=0(root) gid=0(root) groups=0(root) Maybe it is redundant for groups=0(root) listed here, gid=0(root) can express the meaning of group **root** 's id is 0?

What the `id` command lists is

1. The effective user ID and username of the user running `id`,
2. The effective group ID and group name of same user,
3. The list of all supplementary ("secondary") groups that this user belongs to.



In this case, the `root` user belongs to only one group, the `root` group, so this group is listed as the effective group as well as part of the supplementary groups.

On my OpenBSD system:


$ doas id
uid=0(root) gid=0(wheel) groups=0(wheel), 2(kmem), 3(sys), 4(tty), 5(operator), 20(staff), 31(guest)