Path: utzoo!mnetor!tmsoft!torsqnt!hybrid!scifi!bywater!uunet!auspex!guy
From: guy@auspex.auspex.com (Guy Harris)
Newsgroups: comp.unix.questions
Subject: Re: Substitute-User or Super-User ?
Keywords: su, superuser, substitue user.
Message-ID: <5543@auspex.auspex.com>
Date: 27 Jan 91 01:51:58 GMT
References: <868@creatures.cs.vt.edu> <1991Jan26.173253.21396@dg-rtp.dg.com>
Distribution: na
Organization: Auspex Systems, Santa Clara
Lines: 14

>> Was it originally meant to be become-superuser command ?
>
>It's because the default operation of su, as you mention, is to become
>root, who is the super user.

And because, as I remember, the V6 version *only* let you become
super-user; it didn't take an optional "who should I become" argument. 
Back then, it *was* the "super user" command; I guess when they added
the user-name argument, they came up with "substitute user" as the best,
well, umm, what *is* the name for a phrase formed from an acronym? :-)

(Remember, the etymology of UNIX commands is, at times, quirky. 
Consider V6's "dsw" command - no, it's not "Department of Sanitary
Waste", nor is it roughly based on "Do Svidanja".)