bug#13032: 24.3.50; Request: Provide a `delete-duplicate-lines' command

[Dani Moncayo <dmoncayo@gmail.com>]

>>>   C-u M-| awk -- '!a[$0]++' RET
>>
>> Isn't
>>
>>   C-u M-| uniq RET
>>
>> shorter and easier to type?
>
> I use `uniq' only on files where lines are sorted.  OTOH, something like
> '!a[$0]++' that is not limited to consecutive duplicates is better for
> files where lines are not sorted such as log files, etc.

My use cases usually involves compacting a collection of lines
gathered from several places.  So the compacting operation is normally
coupled with a sort operation.

Thus, the command provided by Juanma is good enough for these use
cases (I first do a `sort-lines' and then a `delete-duplicate-lines').

But I agree that it would be even better if `delete-duplicate-lines'
did TRT even when the lines are not sorted.  (I've just tested this
feature in MS-Excel, and it is so: it doesn't requires that the lines
are previously sorted)

Thank you.

-- 
Dani Moncayo