Subject: bug#6393: The meaning of --key of sort command?

From: Eric Blake <[email-masked]>
Date: Thu, 10 Jun 2010 11:01:51 -0600

On 06/10/2010 10:39 AM, Peng Yu wrote:
> Hi,
> 
> I don't think that I completely understand what key means. In the
> following example, I thought that --key=2 should order the lines by
> the 2nd letter in each line without reordering the lines with the same
> 2nd letter. But it turns out my understanding is not correct. For
> example, "u a" was before "a a" sorting, but "u a" is after "a a"
> after sorting.

'--key=2' implies a primary sort key from the second field (not second
letter), through the end of the line, with a secondary sort key of the
entire line.  '--key=2,2' implies a primary sort key of just the second
field, with a secondary sort key of the entire line.  You want
'--key=2,2 --stable', which disables the secondary sort over the entire
line.

-- 
Eric Blake   [email-masked]    +1-801-349-2682
Libvirt virtualization library http://libvirt.org