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bug#16329: `head --lines=-0' prints nothing if no newline at the EOF
From: |
Eric Blake |
Subject: |
bug#16329: `head --lines=-0' prints nothing if no newline at the EOF |
Date: |
Fri, 03 Jan 2014 09:57:25 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 |
On 01/03/2014 08:50 AM, 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.
Per POSIX, 'head' is only required to operate on "text files"
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/head.html
and a "text file" must either be empty or have a trailing newline:
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_397
So this is not necessarily a bug. That said, since POSIX doesn't
specify what we should do, we are free to make it behave differently.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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