Directory hashing

lists at mlserv.org lists at mlserv.org
Mon May 11 11:21:49 EEST 2020



> Am 11.05.2020 um 10:16 schrieb Aki Tuomi <aki.tuomi at open-xchange.com>:
> 
> 
>> On 11/05/2020 11:10 Simone Lazzaris <s.lazzaris at interactive.eu> wrote:
>> 
>> 
>> In data lunedì 11 maggio 2020 10:00:38 CEST, lists at mlserv.org ha scritto:
>>> Hi,
>>> 
>>> I struggle with directory hashing. I want something like this:
>>> 
>>> /srv/mail/c/cf37a8dff5e360927ba10ab2
>>> 
>>> The final folder is simpel, as it is:
>>> 
>>> %{sha256;truncate=96:user}
>>> 
>>> But how do I get a first level from sha256? Unfortunately, the truncate
>>> option aligns only full 8bit and does not divide into low and high nibbles.
>>> How can I express this for sha256?
>>> 
>>> in MD5 this would be %1Mu
>>> 
>>> Many thanks in advance
>>> 
>>> Christian
>> 
>> Maybe as a workaround you can create a directory named /srv/mail/c and make 16 
>> symbolic links to it: /srv/mail/c0, /srv/mail/c1, /srv/mail/c2,  up to /srv/
>> mail/cf.
>> 
>> In that way you can use truncate=8.
>> 
>> 
>> 
>> -- 
>> Simone Lazzaris
>> QCom SpA
> 
> Out of curiosity, but why do you use SHA256? You get probably no extra benefit from it. I mean, you are free to do so, but ... why?

The reason for me was that I could bash script a transition from username to directory:

echo -n "username" | sha256sum | cut -c 1-24

That way I could convert all folders easily. I did not know how to do this with the M-versions.

> 
> Anyways, it would work pretty much the same way, %1{sha256:..} and %4{sha256:...}.

Thanks. I will try that out.

Christian

> 
> Aki

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