So, I have a file that contains a line like:

foo.bar.bletch.one.two

where the dots represent null (\0) characters.

I want to be able to grep this line, using this command:

grep foo.bar.bletch.one.two file

where the dots represent actual dots (regexp wildcards).
(I do it this way because I don't know how to represent a null character in
a grep RE; using dots instead gets you a "good enough for government work" result)

Interestingly, in grep version 2.20, this worked as expected, but in grep version 3.3, it fails. I found this out when the above code stopped
working, when the code was moved to a newer Linux system (which had the new version of grep installed).

This is all out of curiosity, of course. I know this is a grey area in
terms of standards and stuff like that, but it seems odd that they would actually removing working functionality. The man page says little on the subject; it does mention nulls in a few places, but it seems not relevant
to this issue.

Anyway, I switched the code to use GNU AWK (Gawk), which explicitly
supports nulls in strings, so no worries there. The Gawk solution is shorter and cleaner anyway.

--
"They say if you play a Microsoft CD backwards, you hear satanic messages.
Thats nothing, cause if you play it forwards, it installs Windows."

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On 2025-04-12, John McCue <jmccue@magnetar.jmcunx.com> wrote:

Kenny McCormack <gazelle@shell.xmission.com> wrote:

So, I have a file that contains a line like:

foo.bar.bletch.one.two

where the dots represent null (\0) characters.

I want to be able to grep this line, using this command:

grep foo.bar.bletch.one.two file

Did you try using argument '--binary-files=' ?
Detail in the GNU grep man page :)

I just remember the -a shortcut, which is the same
as --binary-files=text. All the other --binary-files
options are about /not/ grepping through binary files,
so that useful one gets the one letter shortcut.

We can probably mnemonize it as "all": "grep
through all the darned files, including binaries".

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Kenny McCormack <gazelle@shell.xmission.com> wrote:

So, I have a file that contains a line like:

foo.bar.bletch.one.two

where the dots represent null (\0) characters.

I want to be able to grep this line, using this command:

grep foo.bar.bletch.one.two file

Did you try using argument '--binary-files=' ?
Detail in the GNU grep man page :)

<snip>

--
[t]csh(1) - "An elegant shell, for a more... civilized age."
- Paraphrasing Star Wars

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