======================================================== "jonkx using on | May 31, 2010 at 10:22 am | Permalink
I worked with the Unix OS from the early 1980′s (at first we ran early versions on a DEC PDP-11) until 1992. Starting in 1992, I did contract work on proprietary versions based on SVR4.
It was just easier to say the initials “S U” or “super-user” than to say “switch user” or “substitute user”. To insist on correctness, whether authoritarian, historical or otherwise seems petty.
Depending on the options used, su can be used to switch user, substitute user or become “super user”. Success depends on knowledge of the appropriate password. “sudo” on the other hand may allow one to become any other user (depending on the configuration of sudo and being a “sodoer”) knowing only the login password.
On the systems I have used, a sudoer can become root (“super user”) using this shell command at a terminal:
sudo su – root
and responding to the prompt with the login password used to sign in the current user.
I think it is important to point out that you cannot become “super user” or root from a shell with the su command alone unless there is a root password and that password is entered at the prompt. =========================================