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From: ugfailau@sunybcs.uucp (Fai Lau)
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: Weird things in csh (and kernel?)
Message-ID: <8849@sunybcs.UUCP>
Date: 26 Feb 88 23:49:24 GMT
References: <1193@ark.cs.vu.nl>
Sender: nobody@sunybcs.UUCP
Reply-To: ugfailau@joey.UUCP (Fai Lau)
Organization: SUNY/Buffalo Computer Science
Lines: 40

In article <1193@ark.cs.vu.nl> maart@cs.vu.nl (Maarten Litmaath) writes:
>Has anyone noticed the following oddities?
>1)
>	% a.out < a.out
>	a.out: Text file busy.
>	%
>
	This is not as bad as this,

	cat file | grep john > file

	There will be nothing withsoever in file "file". UNIX is kinds
strange when you put the same file name at both "ends" of a pipeline or
redirect. Aviod doing it or sooner or later you'll find out some files
you're working on would be strangely deleted against your wish. Speaking
from experience here.

>Why shouldn't a process be able to read its text file?
>2)
>	% cat ~/.cshrc
>	echo echo hello
>	% cp /bin/echo .
>	% ./echo > echo
>	hello: Command not found.
>	% cat echo
>	echo hello
>	hello
>	%
>
	Find the source code echo.c, compile it, put the executable in you
directory, and the problem would go away. The only explanation
I can give for the phenomonen is that for some reason csh wants to
parse .cshrc, and somehow thinks hello is a command. I'm using
tcsh in /usr/local/bin and I got the error message "/bin/tcsh: not
found" until I restarted with csh did I got the behavior you
described.

Fai Lau
SUNY at Buffalo (The Arctic Wonderland)
UU: ..{rutgers,ames}!sunybcs!ugfailau
BI: ugfailau@sunybcs INT: ugfailau@joey.cs.buffalo.EDU