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bug#9995: problem about sort -u -k
From: |
Eric Blake |
Subject: |
bug#9995: problem about sort -u -k |
Date: |
Wed, 09 Nov 2011 07:58:42 -0700 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.23) Gecko/20110928 Fedora/3.1.15-1.fc14 Lightning/1.0b3pre Mnenhy/0.8.4 Thunderbird/3.1.15 |
[Let's keep the list in the loop]
On 11/08/2011 07:58 PM, 夏凯 wrote:
thanks for you reply.
if i want to get my result, whether should i use sort -u -k3 -k1 -k2 a
to do that?
I'm still not quite sure what result you want.
sort -u -k3 -k1 -k2 a
says to sort with three keys - from field 3 to the end of the line, from
field 1 to the end of the line (aka the entire line), and from field 2
to the end of the line (that -k2 is useless, since sorting by field 1 to
the end of the line already sorted everything so that there is no longer
any distinguishing factors from field 2 to the end of the line). Then,
after sorting, sort discards any lines where all three keys are
identical, and since the -k1 key was the entire line, you are discarding
only duplicate lines. But I don't know if that is what you wanted.
--
Eric Blake address@hidden +1-801-349-2682
Libvirt virtualization library http://libvirt.org