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From: arnold@ucsfcgl.UUCP (Ken Arnold%CGL)
Newsgroups: net.unix
Subject: Re: Alternate Shells
Message-ID: <615@ucsfcgl.UUCP>
Date: Fri, 16-Aug-85 23:43:51 EDT
Article-I.D.: ucsfcgl.615
Posted: Fri Aug 16 23:43:51 1985
Date-Received: Mon, 19-Aug-85 22:03:52 EDT
References: <10672@Glacier.ARPA> <575@bu-cs.UUCP>
Reply-To: arnold@ucsfcgl.UUCP (Ken Arnold)
Organization: UCSF Computer Graphics Lab
Lines: 23

>>From: conor@Glacier.ARPA (Conor Rafferty)
>>Subject: Alternate Shells
>>Summary: Why is chsh fascist?
>
>>A quickie: 4.2BSD chsh does not allow the user to specify alternative
>>shells - only "sh" and "csh" are permitted. Why is this? It seems
>>ironically inappropriate in UNIX, where the shell is ``an ordinary,
>>swappable user program'' and ``user-selectable system interfaces [...]
>>become essentially trivial to implement'' [Ritchie & Thompson CACM 1974].
>
>One obvious reason probably had more to do with the 'nuisance' of people
>setting various things to be their shell and then finding out it was a
>bad choice...

I helped make this decision -- it was because people who left their
terminals unattended for a few minutes (to relieve themselves, say)
would find themselves with a strange shell the next time they logged
on.  This kind of prank became such a pain (besides being virtually
unfixable without finding a super-user, a species of (alleged) person
not always available when you have an assigment due the next morning)
that we decided to turn off chsh to non-normal shells except for root.

		Ken Arnold