GNU bug report logs - #17799
grep 2.5.4 ignoring parts of expression

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Jim Michaels <jmichae3 <at> yahoo.com>
To: "bug-grep <at> gnu.org" <bug-grep <at> gnu.org>
Subject: grep 2.5.4 ignoring parts of expression
Date: Wed, 18 Jun 2014 01:53:16 -0700

[Message part 1 (text/plain, inline)]

grep random "#include <(bits/)?random(\.h)?>" *
expected: on the include/c++/bits dir of a gcc compiler should produce a couple of results. 

actual: produces pages and pages with just about every file in it. anything with the word random in it. grep is ignoring #include <(bits/)? and (\.h)?> and I have no clue why.

all I wanted was the header files in the compiler which #included anything related to random.h because I had a bug in gcc I was trying to report, so I ended up finding a bug in grep too.


 
-------------
Jim Michaels
Jmichae3 <at> yahoo.com
JimM <at> RenewalComputerServices.com
http://RenewalComputerServices.com
http://JesusnJim.com (my personal site, has software)
---
IEC Units: Computer RAM & SSD measurements, microsoft disk size measurements (note: they will say GB or MB or KB or TB when it is IEC Units!):
[KiB] [MiB] [GiB] [TiB]
[2^10B=1,024^1B=1KiB]
[2^20B=1,024^2B=1,048,576B=1MiB]
[2^30B=1,024^3B=1,073,741,824B=1GiB]
[2^40B=1,024^4B=1,099,511,627,776B=1TiB]
[2^50B=1,024^5B=1,125,899,906,842,624B=1PiB]
SI Units: Hard disk industry disk size measurements:

[kB] [MB] [GB] [TB]
[10^3B=1,000B=1kB]
[10^6B=1,000,000B=1MB]
[10^9B=1,000,000,000B=1GB]
[10^12B=1,000,000,000,000B=1TB]
[10^15B=1,000,000,000,000,000B=1PB]

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Message #10 received at 17799-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Jim Michaels <jmichae3 <at> yahoo.com>, 17799-done <at> debbugs.gnu.org
Subject: Re: bug#17799: grep 2.5.4 ignoring parts of expression
Date: Wed, 18 Jun 2014 08:32:18 -0700

Jim Michaels wrote:
> grep random "#include <(bits/)?random(\.h)?>" *
> expected: on the include/c++/bits dir of a gcc compiler should produce a couple of results.
>
> actual: produces pages and pages with just about every file in it. anything with the word random in it

That's because your command asked to find the word 'random'.  It's of 
the form:

grep random LIST-OF-FILE-NAMES

The first file name is "#include <(bits/)?random(\.h)?>", which grep 
complained to you about.

Message #13 received at 17799 <at> debbugs.gnu.org (full text, mbox):

From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: Jim Michaels <jmichae3 <at> yahoo.com>
Cc: 17799 <at> debbugs.gnu.org
Subject: Re: bug#17799: grep 2.5.4 ignoring parts of expression
Date: Thu, 19 Jun 2014 00:36:41 +0900

If you don't specify any options, grep regards a pattern as BRE.

http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_03

(', `)' and `?' are treated as normal character in BRE.  If you expect
that they are treated as special character, you must escape them with
backslash.

BTW, I see you want to use ERE.

http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04

If so, you must specify -E option.  I test below on Fedora 20.

$ cd /usr/include/c++/4.8.2
$ grep -E "#include <(bits/)?random(\.h)?>" * 2>/dev/null
$ grep "#include <(bits/)?random(\.h)?>" * 2>/dev/null
random:#include <bits/random.h>

Message #16 received at 17799 <at> debbugs.gnu.org (full text, mbox):

From: Sekar Sundaram <inventsekarinfo <at> gmail.com>
To: 17799 <at> debbugs.gnu.org, eggert <at> cs.ucla.edu, jmichae3 <at> yahoo.com
Subject: Re: bug#17799: grep 2.5.4 ignoring parts of expression
Date: Thu, 19 Jun 2014 13:41:37 -0500

[Message part 1 (text/plain, inline)]

Hi Jim,
Lets say i want to search for "#include <bits/c++config.h>" (on my machine,
i could not find any random.h under c++ directory) and this below grep
command works fine for me..

dev-RH: root - redhat[/usr/include/c++/4.1.1]
*# grep -r "#include <bits/c++config.h>" **
backward/alloc.h:#include <bits/c++config.h>
backward/function.h:#include <bits/c++config.h>
backward/heap.h:#include <bits/c++config.h>
backward/pair.h:#include <bits/c++config.h>
.....
.....

maybe, lets search random.h under all subdirectories(-r) and only one
output per file(-m 1) will ok, to avoid screen full of texts.
*grep -r -m 1 "random.h" * *

Let us know if still you are facing any issues.

Have a great day!

*Best Regards,*

*Sekar *

*The smallest things can have the biggest impact. Look inside. - Intel*




On Wed, Jun 18, 2014 at 10:32 AM, Paul Eggert <eggert <at> cs.ucla.edu> wrote:

> Jim Michaels wrote:
>
>> grep random "#include <(bits/)?random(\.h)?>" *
>> expected: on the include/c++/bits dir of a gcc compiler should produce a
>> couple of results.
>>
>> actual: produces pages and pages with just about every file in it.
>> anything with the word random in it
>>
>
> That's because your command asked to find the word 'random'.  It's of the
> form:
>
> grep random LIST-OF-FILE-NAMES
>
> The first file name is "#include <(bits/)?random(\.h)?>", which grep
> complained to you about.
>
>
>
>

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