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To: Dan Cross <crossd@gmail.com>
In-reply-to: Your message of "Tue, 10 Mar 2020 13:38:23 -0400."
 <CAEoi9W4nNbUT6_NnJGsgWFPj4GHTeupmDVpZAMZRw8-70wnk+w@mail.gmail.com>
References: <202003101615.02AGFLgS075920@coolidge.cs.dartmouth.edu>
 <CAEoi9W4nNbUT6_NnJGsgWFPj4GHTeupmDVpZAMZRw8-70wnk+w@mail.gmail.com>
Comments: In-reply-to Dan Cross <crossd@gmail.com>
 message dated "Tue, 10 Mar 2020 13:38:23 -0400."
From: Bakul Shah <bakul@bitblocks.com>
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Date: Tue, 10 Mar 2020 10:44:32 -0700
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Subject: Re: [TUHS] Command line options and complexity
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Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>,
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On Tue, 10 Mar 2020 13:38:23 -0400 Dan Cross <crossd@gmail.com> wrote:
>
> This begs questions of stability: in the event of non-unique keys and
> non-key fields in the sortable data, which "records" (lines) are kept and
> which are discarded? Surely the "first" is kept and subsequent entries with
> the same key suppressed, but I confess I don't know enough about the
> internals of sed to know even what algorithm it uses (I assume a disk-based
> merge sort?), but I would imagine these details have changed over time.

FreeBSD manpage for sort says that -u implies a stable sort,
similar to -s.