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

From: Eric Blake <[email-masked]>
Date: Fri, 03 Jan 2014 10:10:09 -0700

On 01/03/2014 10:02 AM, Pádraig Brady wrote:
>>> 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.
> 
> BTW I still don't think POSIX is specifying that text files without
> a trailing newline are not text files.
> 
> It states that text files can have zero or more lines,

Where "lines" is also a well-defined POSIX term:
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206

> implying that the trailing new line is optional.

Wrong.  The trailing newline character is mandatory in text files.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org