bsd-grep-20080725_1 -v flag busted...

[Paul Schmehl]

--On Monday, August 04, 2008 22:24:21 +0200 Daniel Roethlisberger 
<daniel at roe.ch> wrote:

> Gábor Kövesdán <gabor at FreeBSD.org> 2008-08-04:
>> Chuck Swiger escribió:
>> > I'd just updated the BSD grep port to bsd-grep-20080725_1, but
>> > regrettably have noticed that many things using grep stopped working.
>> > For example, running GNU-style ./configure hangs here:
>> >
>> >  configure: creating ./config.status
>> >  load: 1.15  cmd: sh 72964 [runnable] 7.60u 95.78s 14% 2260k
>> >
>> > A trivial test case:
>> >
>> > % echo 'fee\nfi\nfoe\nfum' | ./grep -v fi
>> > % echo 'fee\nfi\nfoe\nfum' | /usr/bin/grep -v fi
>> > fee
>> > foe
>> > fum
>> > % ./grep --version
>> > grep (BSD grep) 2.5.1-FreeBSD
>> Hello Chuck,
>>
>> thanks for your notes. It seems very strange to me, because GNU grep
>> produces the same output for me. Apart from this, the -v flag was really
>> broken, but I applied some fixes before updating the port and in the
>> version, which I committer, I thought that the -v flag was compatible.
>>
>> Here is what I get at the moment:
>>
>> > echo 'fee\nfi\nfoe\nfum' | ./grep -v fi
>> > echo 'fee\nfi\nfoe\nfum' | /usr/bin/grep -v fi
>> > /usr/bin/grep -V
>> grep (GNU grep) 2.5.1-FreeBSD
>>
>> Copyright 1988, 1992-1999, 2000, 2001 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions. There is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>>
>>
>> It's still the same, thus I don't understand how you could produce that
>> output with GNU grep.
>
> I may be stating the obvious, but note that depending on your shell and
> it's configuration, echo might not translate \n to an actual newline.
> You might need to use `echo -e' instead of `echo' to get four lines
> printed instead of one.  /bin/sh and bash need it, ksh doesn't, not sure
> about (t)csh.  Also note that our /bin/echo doesn't know about -e and
> will never translate \n to a newline.  The following should be more
> portable across different shells:
>
> printf 'fee\nfi\nfoe\nfum' | ./grep -v fi
> printf 'fee\nfi\nfoe\nfum' | /usr/bin/grep -v fi

Indeed:

pauls at utd65257# echo -e 'fee\nfi\nfoe\nfum'
fee
fi
foe
fum
pauls at utd65257# echo -e 'fee\nfi\nfoe\nfum' | grep -v fi
fee
foe
fum

-- 
Paul Schmehl, Senior Infosec Analyst
As if it wasn't already obvious, my opinions
are my own and not those of my employer.
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