grep for ascii nul

[Dale Scott]

There are ports for many GNU utilities, and BSD has a long history of staying pure to its roots (IMHO), so why not just install gnuawk and symlink awk to gnuawk?

Cheers,
Dale


----- Original Message -----
> From: "Victor Sudakov" <vas at sibptus.ru>
> To: "freebsd-questions" <freebsd-questions at freebsd.org>
> Sent: Sunday, November 3, 2019 9:47:56 AM
> Subject: Re: grep for ascii nul

> Kurt Hackenberg wrote:
>> 
>> > I'm a big fan of awk, awk is in the base system and should be able to do
>> > it, right?
>> > 
>> > $ hd trees.txt
>> > 00000000  66 69 72 0a 6f 61 6b 0a  63 65 64 00 61 72 0a 62  |fir.oak.ced.ar.b|
>> > 00000010  69 72 63 68 0a 70 61 6c  6d 0a                    |irch.palm.|
>> > 0000001a
>> > $
>> > 
>> > Note the ascii null embedded in the word "cedar"
>> > 
>> > $ awk '/\x66\x69/{print $0}' trees.txt
>> > fir
>> > 
>> > So far so good. But with the ascii nul it behaves in an unexpected way:
>> > 
>> > $ awk '/\x00/{print $0}' trees.txt
>> > fir
>> > oak
>> > ced
>> > birch
>> > palm
>> > $
>> 
>> Looks like it has the same problem that I guess grep does: it takes that
>> NUL as the end of a C string, so the regexp becomes a null string (zero
>> length), which matches everything.
> 
> You know what, lang/gawk does not have this problem:
> 
> $ gawk '/\x00/{print $0}' trees.txt
> cedar
> $
> 
> This is not the first time BSD AWK sucks in comparison with GNU AWK :-(
> 
> Do you think this is worth a PR?
> 
> --
> Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
> 2:5005/49 at fidonet http://vas.tomsk.ru/