Date: Sun, 3 Nov 2019 10:23:02 -0700 (MST) From: Dale Scott <dalescott@shaw.ca> To: Victor Sudakov <vas@sibptus.ru> Cc: freebsd-questions <freebsd-questions@freebsd.org> Subject: Re: grep for ascii nul Message-ID: <1183473267.187448543.1572801782450.JavaMail.zimbra@shaw.ca> In-Reply-To: <20191103164756.GA50239@admin.sibptus.ru> References: <20191101092716.GA67658@admin.sibptus.ru> <63808.1572638827@segfault.tristatelogic.com> <20191102064505.GA98558@admin.sibptus.ru> <7775e7f8-89ba-d057-67d3-cdcb92d2bbb4@panix.com> <20191103164756.GA50239@admin.sibptus.ru>
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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@sibptus.ru>
> To: "freebsd-questions" <freebsd-questions@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@fidonet http://vas.tomsk.ru/
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