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From: amir@booboo.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: A Lethal Command
Message-ID: <372@booboo.UUCP>
Date: Wed, 3-Jun-87 13:54:07 EDT
Article-I.D.: booboo.372
Posted: Wed Jun  3 13:54:07 1987
Date-Received: Sat, 6-Jun-87 04:29:02 EDT
References: <3163@well.UUCP> <853@aluxz.UUCP>
Organization: Gould CSD, Fort Lauderdale, FL
Lines: 31

In article <853@aluxz.UUCP>, ndp@aluxz.UUCP (N. D. Parikh) writes:

> >     I have recently discovered, however, that all of my previous work
> >was entirely unnecessary.  An MS-DOS system can be brought to a grinding
> >halt with a single command:
> >
> >		echo >"="
> > (Deleted Text).
> I tried this on my 6300 and first time I made a typing mistake (booo!).
> I found that it still worked. (i.e. 'dcho >"=" '). so I tried a few
> combinations. What I found was that the minimum you need to do to bring
> down the machine is just type >"=". Anything before '>' is don't care.
> Interesting. Anybody know the reason ?
> 

Sure.  That's because command.com like sh on Unix tries to handle the
output redirection first before executing the command.  The problem must
be in the file creation routine in MS-DOS.

I wonder what the signifcance of "=" is though.  Does it have some
undocumented special meaning (like wildcards)?






-- 
Amir H. Majidimehr
Gould Inc, Computer Systems Division
{sun,pur-ee,brl-bmd}!gould!amir