Read not honouring "-r"?

Igor Peshansky pechtcha@cs.nyu.edu
Tue Sep 19 15:38:00 GMT 2006


On Tue, 19 Sep 2006, Williams, Gerald S (Jerry) wrote:

> Doug Irwin wrote:
> > One would expect a "read -r fs t2 t3" to process this without
> > attempting to expand slashes.  But I can't seem to get this bit
> > working... And I can't seem to find any doco on doing that in Cygwin.
> >
> > I've attached the files I am testing with in the hope that someone
> > can help me work this out.
> >
> > No doubt I have missed something rather obvious.
>
> "-r" has nothing to do with it: CR/LF line endings are the
> culprit.
>
> This seems to be particularly tied to ksh, and specifically
> when you use "<" to redirect a file. If you simply pipe the
> output of grep to the while loop, it works. Interestingly,
> sh, bash, and zsh all give the behavior you were expecting.

Thanks for the detective work, Jerry -- I almost missed the textmode
issue.

> So for the short term, run d2u on filesystems.cfg. If you
> plan to continue using ksh, you may want to follow up and
> try to understand the discrepancy--there may be an option
> that allows you to get the behavior you want (and if not,
> it may be worth having KSH's behavior changed to be more
> consistent with other shells, but that's something for
> the maintainer and/or upstream KSH support to decide).

Unfortunately, there is no option to control this.  Neither is there any
upstream KSH support.  The "quick fix" I mentioned in the previous message
simply disables seeking and buffering everywhere in PDKsh, so expect
slowdowns with large scripts/data files in the new version.  But at least
it'll be correct.
	Igor
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