bug#16329: `head --lines=-0' prints nothing if no newline at the EOF

[Pádraig Brady]

On 01/03/2014 03:50 PM, Алексей Шилин wrote:
> Hi,
> 
> If one runs `head --lines=-0 somefile', he'll sometimes get no output instead 
> of full file contents as
> expected after reading the manual:
> 
> -n, --lines=[-]K
>         print the first K lines instead of the first 10; with the lead‐
>         ing `-', print all but the last K lines of each file
> 
> It depends on whether the file has a trailing newline.
> 
> For example:
> 
> $ printf '1\n2\n3' > test1
> $ printf '4\n5\n' > test2
> $ head -n -0 test*
> ==> test1 <==
> 
> ==> test2 <==
> 4
> 5
> $ tail -n +0 test*   # Just for comparison
> ==> test1 <==
> 1
> 2
> 3
> ==> test2 <==
> 4
> 5
> $ 
> 
> I'm using Debian GNU/Linux 7 wheezy and coreutils-8.13; I've also tested 
> coreutils-8.22, and it has the
> same issue.
> 
> A proposed patch fixing the bug is attached. It makes head behave exactly 
> like `tail -n +0' on same files.
> 

Thanks for the clear reproducer and patch.
I'll probably apply this in your name with a test.

thanks!
Pádraig.