[TUHS] V9 shell [was Re: Warner's Early Unix Presentation]

Larry McVoy lm at mcvoy.com
Tue Feb 11 13:53:40 AEST 2020


On Mon, Feb 10, 2020 at 10:32:58PM -0500, Doug McIlroy wrote:
> > What i like is the autocorrect feature in v8:
> >
> > $ cd /usr/blot
> > /usr/blit
> > $ pwd
> > /usr/blit
> 
> Here I am, editor of the v8 manual and unaware of the feature.
> We now know that silent correction is a terrible idea.

I had the same thought,

cd /some/place/I/want/to/remove
$PWD is /some/place/I/want/dont/remove
rm -rf ./*

oops.

> Postel's principle: "be conservative in what you do, be liberal
> in what you accept from others" was doctrine in early HTML
> specs, and led to disastrous disagreement among browsers'
> interpretation of web pages. Sadly, the "principle" lives on 
> despite its having been expunged from the HTML spec.

I think Jon had the right intentions.  HTML is different than
a command prompt.

> I didn't like some Lisp systems' DWIM (do what I mean) when I
> first heard about the feature, and I like it even less 40-some
> years on. I would probably have remonstrated with Rob had I
> realized the shell was doing it.

Yep, agreed.   There are places where that works and there are most
definitely places where they do not.  The shell should not guess.


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