[olug] sort -u vs uniq

[Herb Wolfe]

I have a e-book on shell scripting that covers almost this exact situation.
It is sorting the hosts file, so doesn't use unique, but the rest is the
same.

sort -t. -k1,1n -k2,2n -k3,3n -k4,4n -u

Where -t. Is used to specify the . as the delimiter, while -k1,1n indicates
that the first key is field 1 to 1, inclusive, and is numeric, rather than
alphabetical.

On Mar 13, 2017 10:23 AM, "Noel Leistad" <noel at metc.net> wrote:

I'm trying to get a list of uniq IP addresses from a log file. I have a
list of ALL IP addresses. Using sort -nu and sort -n | uniq give me 2
different lists.

A stare and compare make me think that sort -nu  only considers the first 2
octets as significant. RTFM of the sort man page indicates sort honors
LC_COLLATE.

<appear uninformed>
LC_COLLATE isn't in env, so I'm assuming it's set at build/compile time
when building sort or in the c libraries someplace?
</appear uninformed -- hardly, stupid probably better tag... and not
closed.>

Could this be why the sort -u and uniq return differing output? I don't see
anyplace to specify "how much" to consider significant when running sort.
Anyone care to offer thoughts?

Thanks.


Noel

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