How do i create a user who has all the rights of a super user(root).

useradd username -g group1 -G group2,group3,group4

I think that should be:

useradd -u 0 -o -g root username

The only problem is the system will still see you as root instead of the new user since the entry for root falls first in /etc/passwd.

What exactly are you trying to accomplish? Why not just use root?

nah, my way is nicer. and it makes more sense to add the user to root as an additional group, rather that just using root as the main group. you should be able to create a normal user gid > 500 as a memerb of the root group, you'll get less error warnings and such lik as well i presume. not actually BEING root there might be a few things they couldn't do, if the group mask is not set on certain files. your way simply renames root to someone else, which i would guess could very easily screw a system over.

Yeah, I know, thus the warning in my message. Actually I've tried it on other systems and it doesn't screw things up... all it does is allow you to have another name/password to become root, because once you login, the system still equates you to uid 0 and you just look like root. You don't even have the new username.

Just putting a user in the root group doesn't give him "all the rights of a super user(root)" as the poster requested. At most it gives permissions to some of roots files.

I have a hunch that sudo will accomplish what he's wanting, but until we know exactly what that is, there's no way to tell... maybe he wants to rlogin from another system as a regular user and become root on the Linux machine /shrug.

If he's wanting all of root's rights, why doesn't he just use root's account?