[debbugs-tracker] bug#11631: closed (Head command does not position file pointer correctly for negative line count)

[GNU bug Tracking System]

Your message dated Tue, 05 Jun 2012 22:35:13 +0200
with message-id <address@hidden>
and subject line Re: bug#11631: Head command does not position file pointer 
correctly for negative line count
has caused the debbugs.gnu.org bug report #11631,
regarding Head command does not position file pointer correctly for negative 
line count
to be marked as done.

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-- 
11631: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=11631
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> --- Begin Message ---
>
>
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> Subject: 
>
> Head command does not position file pointer correctly for negative	line count
>
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>
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> Date: 
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> Tue, 5 Jun 2012 15:07:19 +0530
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> Head command does not position file pointer correctly for negative line count. Here is a demonstration of the problem.
>
> Step 1 - Create a file with 10 lines in it.
> $ yes "ABC" | head -c 40 >ip.txt 
>
> $ 
>
> Step 2 - If head behaves correctly, then 2 lines should get printed after "------------" but nothing gets printed!
> $ (head -n -2; echo "------------------------"; cat) <ip.txt
> ABC
>
> ABC
> ABC
> ABC
> ABC
> ABC
> ABC
> ABC
> ------------------------
> $ 
>
> Step 3 - Another try fails. If head behaves correctly, then 8 lines should get printed after "------------" but nothing gets printed!
>
> $ (head -n -8; echo "------------------------"; cat) <ip.txt
> ABC
> ABC
> ------------------------
> $ 
>
>
>
> /*****************************************************************************************************************************/
>
> Possible cause of the defect -> Following snippet is copied from head.c (Function - elide_tail_lines_seekable ). Perhaps, there should be a lseek after fwrite there...:
>
>               /* Output the initial portion of the buffer
>
>                  in which we found the desired newline byte.
>                  Don't bother testing for failure for such a small amount.
>                  Any failure will be detected upon close.  */
>               fwrite (buffer, 1, n + 1, stdout);
>
> /*****************************************************************************************************************************/
>
>
> --- End Message ---
> --- Begin Message ---
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>
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> Subject: 
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> Re: bug#11631: Head command does not position file pointer correctly	for negative line count
>
>
>
>
> Date: 
>
> Tue, 05 Jun 2012 22:35:13 +0200
>
>
>
>
> Jim Meyering wrote:
> > Thanks, and thanks for the review.  Pushed.
>
> And with this message, I've closed the issue.
>
>
> --- End Message ---